Mustang GT, Cobra, and Mach 1 Mod Analysis Thread


Computer Geek
Car - 1998 Mustang GT, 5spd

Mod - Mac O/R Prochamber

I was nervous before installing this due to different opinions about the volume level. After driving the car around for 2 days now I can say I love the sound and it is not overly loud. It's a lot deeper, and a bit more "snarly"(I made that word up I think).
Power-wise, I can definitely notice the difference. The car pulls quite a bit harder at the top of first and through second. At higher speeds it also seems to pull a bit harder.


Retired Admin
2004 Mustang GT 4-spd

Accufab 75mm TB - $218 shipped

I replaced my ported stock TB with this one. I already have a ported plenum, so it fit nicely without any needed modifications. The difference in throttle response, even from a ported tb, was incredible. I have yet to go WOT to test the top end, but the car does seem to pull smoother and produce a little more 'umph' on demand. Th epolished job on the Accufab is also top-notch. Incredible quality, looks, and throttle response gains.


Green Means GO!!!
The Sickness Project

2003 Mustang GT

Flowmaster Catback - Great Sound and nice seat of the pants difference (guessing about 5 hp)

Baseline Dyno Run - 216hp/257ft-lbs

SCT Chip (Tuned by - 89 program was good for 10 hp/13 ft-lbs, the difference in shifts alone made this a must buy... easily the best money I've spent on the car. I haven't had a chance to dyno the 93 program but it was good for [email protected]

89 Oct Program Dyno - 226hp/270ft-lbs

MAC Prochamber - Adding this with the Catback gave my car a great sound and added a little giddy up as well.

Here's the list that is currently being installed and is yet to be tested ..


Exhaust ....................Ceramic LT's, Prochamber, MAC Catback Rearend ....................3.73 gears
Engine Management ....SCT Chip
K-Member ..................AJE RR Tubular K-Member
Springs ......................Eibach
Struts .......................Bilstein
Shocks ......................Bilstein
Wheels ......................17x9/17x10.5 Chrome Deep Dish Bullitts
Tires .........................BFG Drag Radials
Chassis Stiffening ........Kenny Brown Subframes
Hood ........................H.O. Fibertrends Cowl Hood
Brakes ......................Stock w/ LineLock


New Member
lets see....

with a Densecharger CAI, MAC o/r H pipe, and Bassani catback I put down 241/273 on the dyno. I did have 4.10 gears at the time so that stole a little HP.

4.10 gears they are fun but cause too much spinning and actually seemed to hurt me at the track.


New Member
1997 Mustang Cobra.

-3.73 Gear
-Big open element K&N
-Offroad H-pipe
-Flowmaster 40's
-Steeda Tri-Ax
-Custom Diablo Revolutions Dyno Tune
-MSD Wires
-Blaster Coils
-Eibach 2" drop springs
-Unknown brand Shorty Headers that I discovered while changing head gaskets

With all the above I have 299 rwhp and 297 rwtq

Best 1/8 run before the wires, coils, and tune- 8.8 at 81
Best 1/8 run after- 8.6 at 83 :thumbup:

I wanna get some stock sixxer rear springs to put in just for the track and get myself some 8.4's. The Eibach lowering springs killed the car's launch. :thumbdown: But they do everything else better :thumbup:


I bent my wookie
01 mustang GT T45 tranny


magnaflow cat back
mac OR/X pipe

(love the sound of my exhaust, smooth but mean)

steeda tri-ax - very nice
upr lower control arms - didn't feel much difference
eibach pro kit springs - just the right drop for me
frpp 70mm TB - seemed to help
SCT xcalibrator tuner - wish I had the xcalibrator 2 now! but it works fine
3.73 gears - perfect for my setup, just a bit of whine

Vortech V2-SQ with aftercooler and custom power pipe and a bunch of accessories.

I spent around $5500 on this tuned. Would have been an amazing deal if it hadn't gone bad but I still payed less then a new kit would have cost me. The car pulls HARD up top now where it use to feel like it was running out of steam. I'll echo what JR said.. I really like how you retain the driveability with the centri style blower. Regular driving isn't difficult but craziness is just a downshift away.


Retired Admin
2004 Mustang GT 4-spd

SLP catted X-Pipe - $175 shipped

I got this from a member. Combined with my Magnaflow catback, the car gives off an awesome sound. The low RPMs and idle are still quiet, but the rest is louder. At higher RPMs (ie: WOT), it sings beautifully. It really is like having a stock car unleashed on the highway in terms of sound. The topend pull is much better now.
The only problem I had was the passenger manifold to midpipe seal. But, this is a very common problem. The quality is topnotch and fitment was perfect. The only thing to watch out for is the catted x-pipe reduces ground clearance by roughly 1 inch.


1995 Mustang GT [5 Spd]

Power mods
Under drive pulleys -$90 (waste of money)
95 Cobra intake - $300 shipped (Home ported lower)
NOS Gt40 Plate kit - $650 (2 10lb bottles,Heater,MSD Digital Window switch,etc.)
2 1/4 SS X pipe - $90 (off my old V6, too small for the V8)
Spintech Pro street dumps- $120 (3 inch entrance/exit. also off V6)

Ford racing aluminum drive shaft - $215
Smog/EGR system Delete - $120ish (with smog bypass pulley and Egr delete kit)

Thats all the 'Performance' mods i have,Stock everything minus whats listed above. N/A The car made 205 rwHP, on 150 shot (crank) of nitrous it made 311 RWHP/400 RWTQ. The engine is still VERY restricted, Cobra intake made almost no gain since im still using stock T/B. Looking to get a "Box" upper intake , fox 80 MM T/B, 94-95 Cobra Injectors and Meter, and CAI, expecting a little closer to 330 rwhp on nitrous.

Future plan is to swap in an Incon Twin Turbo H/C/I 351w. Still a pretty long way from that though..Saving up for a bike first.


Most of the mods I've done have been covered but I'll touch on one I did recently that really surprised me. These are only mods *I* have done on this car, not what was already installed when I purchased it. I'll post up a "review" of 4.6 BBK longtube headers and SCT tune here soon as well:

Steeda double hook quadrant/UPR firewall adjuster--$80 together. Basically removes the stock quadrant/adjuster assembly from under the dash and allows for much easier adjustment (and more range) right under the hood. The quadrant is much stiffer than stock and gives more solid and consistent engagements. If you have a stiff aftermarket clutch on your car like me, and want some better pedal feel and more control over the engagement height, definitely get these. Your stock cable is the best one out there, don't replace it. The install was easy as long as you don't mind bending under the dash in slightly uncomfortable positions, haha.

JLT "cold air intake"--$240 shipped (with extras). I replaced my WMS Cold air with this new setup that's getting lots of rave reviews. The JLT gave me a slightly noticeable increase in power over the WMS piece I had on there before. The look is awesome, you have it painted to match your car and can even have flames or custom paint ordered for it. The JLT is a tricky install, however, on the 4V. The smog pump must be moved and some hoses re-routed to allow for the CAI to fit in the fenderwell. If you drive your car in heavy rain often I wouldn't recommend the CAI (the filter is very close to the ground and somewhat unprotected), but JLT does offer a RAI ("ram air intake") that doesn't go down the fenderwell. The quality of the actual pipe mold is good, although most of the hoses could certainly be purchased at a local hardware store. Overall, a good mod, a little pricey but makes good power (dyno results soon with LT's)

Power Slot rotors/Hawk HPS pads/Russell stainless steel brake lines--$480 together, shipped. I wanted more out of the already good stock Cobra setup, and short of upgrading to 4 or 6-pot calipers this is about as good as you can get these brakes. There is no extra noise, very little dust. The pedal feel is tremendous. I feel that with adequate cooling (possibly ducts from the foglights to the rotors) the brakes could survive a full 20 minute open track session. If you are like me and want good performance when stopping the car or turning a corner, too....I would definitely recommend upgrading to SS lines at the least--they made the most profound difference in feel of the three mods. If you have a 96-01 Cobra with the stock brake lines, you need to replace them anyway--the stock units are highly inadequate and are prone to failure.

Maximum Motorsports full length SFC's--$140 shipped, $25 to install. These made one of the most noticeable differences on my car. These were already on the Cobra when I bought it, but I put them on my V6--and the improved feel of the car alone is worth the money. Many of the squeaks and rattles are gone with these installed. The car feels much more solid pulling into sloped driveways and stays much more planted in corners. The rear end of the car actually feels somewhat connected to the front. Be sure to paint the SFC's after installing them to prevent corrosion. MM is the best brand for SFC's out there short of the Griggs in-floor units (that require lots of custom work), these are a must-have mod for ANY Mustang regardless if you race it or not...just to preserve the structural integrity of the car.


Well-Known Member
Stevetama said:
Hoorai!! I'm now an Alumni myself!!

Car - 2004 Pontiac GTO

Trans - Tremec 6 speed

Mods - Corsa cat back

Future mods - CAI, LT Headers, UDP(maybe), putting my subs/amp into this. But who knows when the 'future' is for me, hahaha!

Nice car man, congrats :D :thumbup:


Computer Geek
Car - 1998 Mustang GT, 5spd

Mod - JLT RAI, $185

First off, Jay was an awesome guy to do business with. His customer service was top notch. I ordered my intake on Saturday morning and he had it shipped out the same afternoon. I even ordered a custom color!! I ended up receiving the intake on Monday so one day to ship was excellent!

As for the intake itself. This intake is huge. Pictures do it no justice. The diameter of the piping is really damn big compare to other intakes. Jay painted my intake rio red to match my car and the paint work was excellent. I waxed it up after installing it with some meguires nxt wax and it shined it up really nice.

Installing it was kind of difficult, but not too bad. The hardest part was getting the couplers on to the piping due to the size. Luckily I had a friend over to help out with the install which made it go a lot faster. Gains were what I would expect from an intake, but a bit better. RPMs climb a lot faster and the increased throttle response makes it all worth it.
Once I get my predator programmer I plan on getting a dyno tune which supposedly is needed to see the best results with this intake. Definitely money well spent :thumbup:


Work Hard. Play Hard.
2003 Mustang GT 5-SPD

MAC o/r h-pipe - $100 to go with my flomaster american thuinder catback.... holy ****. It sounds soooo loud and rumbly and good, makes all the girls near me wet i swear. Anyways the car was tuned for no cats previosuly so after putt ing on the h-pipe it feels like i picked up some good amounts of power. Id recommend taking the cats off you V8 to everyone, so badass. :cool:


The Coors Knight
1994 Mustang Cobra
5 speed
Installed part: MGW shifter w/ sport handle
Price: 179.99 + $7 dollars shipping.

Wow. This thing is amazing. No more wet noodle in my hand while driving... it has short fast shifts, spring loaded so no more missing gears, and is nearly just as quiet as the stock piece without the handle vibrating all over the place. This shifter is a must have for anyone with a 5 speed. It came with detailed easy to follow instructions as well as all the parts needed for installation. Great product for 180 dollars.


Not a Mod... Yet
Mods in sig... Bassani X-pipe is very nice sounding, seems to provide good flow, and you can purchase them used cheap (I paid $65 for mine, but $100 is more normal). I highly recommend a 2.5" exhaust to go with it, or even without an upgraded midpipe. That was the first mod I did (car came with mufflers and K&N filter), and I felt a little something in the seat of the pants. The most noticeable mods were the PI intake and cams. People have tested these mods to be good for 30-35rwhp together, or 20-25/10-15hp respectively. I got a screaming deal on my intake and cams (paid $100 for valve covers, one PI head, both cams, and intake manifold), but normally a set of cams can be found for $50-75, and the intake can be found for $75-$125. With these two mods added to my car a chirp in 3rd became getting sideways, and the car starts to break loose at the top of 2nd gear. I would like 4.10s to go along with my mods, but not sure when that's coming. And if the headswap ever comes, I'll make sure to include my opinion on that too ;)


Retired Admin
2004 Mustang GT 4-spd

JLT RAI - $150

To put it simple, an awesome intake. I had a K/N FIPK before and it made a horrible whistling noise under even the slightest throttle thanks to my upgraded tb & plenum. The JLT is extremely quiet and in conjunction with my other mods, I definately felt a difference, especially top end.
You can even order the intake painted in a Mustang color from white to mystichrome. :)
Worth every penny.