So I've pretty much decided on Hooker 2460's, to a Doug's D901 y pipe to a flowmaster catback. My question to anyone who might know, does the Doug's y-pipe support a 2.5 or 3 in catback flange? Looking at it, it appears that it might have the holes to fit either catback, in which case I'm thinking the 3 inch intermediate pipe is the better option.

 

Generally speaking a Y pipe usually will attach to a CAT before it attaches to a intermediate pipe. I went with stock manifolds into a stock Y pipe into a stock inlet / 3in outlet Magnaflow cat into a 3in. Flowmaster American Thunder CAT back . Sounds great IMO. because I'm a Flowmaster guy.
The Flowmaster cat back comes with a 3in. intermediate pipe into 3in. inlet and outlet 80 series muffler and 3in. exit/tips.

 

The Doug's Y-pipe is a de-cat pipe. I don't have to go through emissions anymore, so I've getting rid of the cat. But I'm assuming if a 2.5" y-pipe will attach to a 3" cat, it should have no issue with a 3" catback?