cliff notes: see last paragraph

I'm looking to do side exit before the tire on my RCSB. Gonna take off the stock cat-back post ball and socket and make a new one using a Spintech single in, dual out. Space is gonna be a premium.

I started to look around at what size tips I want, but the length of said tips is gonna depend what size inlet I want because thats just how the tips are offered. X1 size inlet and Y size outlet come in Z1 or Z2 lengths, or X2 inlet with Y outlet in Z3, Z4 lengths, etc etc.

Long story short, I'm looking at 3" single in, dual 3" out Spintech whose outlet pipes really won't be that long as they're exiting before the rear tire. Will the dual 3" outlets hamper any performance from being rather big for a 4.8, or because they are pretty short and after the muffler it doesn't really matter? Should I really go with 2.5" outlet and weld up an adapter for the tips?

 

I dont think it would hurt anything having that big of pipe after the muffler.....its restricted going through the muffler anyways right? what your doing would be the same as my exhaust system for flow sept i dumped it......