Polishing my banhammer
I'm sorry but it really sounds like you're confused. The pacesetter adapter has rear flanges made to the same style as a GT will have. The rear of the MAC midpipe is made to those same specifications.But Markstang, I cannot use that Mac Dual Exhaust Conversion if I'm also going for long tubes
I could have used the pace adapter with the Dual Exhaust Conversion Kit but it won't work with my long tubes
A GT catback will fit a stock GT midpipe, a MAC v6 shorty H-pipe, a pacesetter v6 midpipe adapter.
A V6 dual exhaust conversion cat-back will fit a stock v6 midpipe and... nope, that's it.
That's why if someone asks me I always say get a GT catback and find an adapter, because it's more versatile and you can reuse the catback if you upgrade exhaust later on.
The v6 dual exhaust conversion catback will not fit the pacesetter adapter. Not because of your longtubes, but because of the midpipe having a different number of flanges. Call or message or somehow contact MAC and ask them if they can send you the flowtubes only (the front two pipes with flanges on both ends) from the GT catback. Explain that you have the v6 catback that hooks to the stock midpipe and would like to avoid buying an entire new catback since the one you have is pretty much the same. I'm trying to save you money.