Why are you asking us?? Why not ask your exhaust friend. You'd have to figure out how much for piping materials, axle-back and resonator.. there you go.

I have a custom setup with 2.5" mandrel bent pipe to a universal dunk muffler. When I first got it done, I had no resonator and it was STUPID LOUD!

I had the shop put a 12" resonator in and it sounds MUCH better. I highly recommend a resonator.