ok i understand what your saying but what my question is the INLET part do i get a 2.25 or a 2.5? cause i plan on getting this

http://www.magnaflow.com/02product/parts/12640.jpg

and i dont have the money to spend for 2 magnaflows and a custom mid pipe. people said getting a custom mid pipe will just make it louder so i just plan on keeping my stock mid-pipe and putting that one i just posted above as my resonator. so would that be ok on my car? i dont care if its lil really lil raspy as long as its not loud as right now...

 

can anyone help me?

 

Are you building a 2.5" mid or a 2.25" mid? If you're building a 2.5" one get the resonator with a 2.5" inlet and outlet. And likewise if you're building a 2.25". I plan to get a 2.5" one done with a 30" resonator.