It's a big jump in volume, expecially when you you romp on it. I have a stock header/cat, a K&N filter in the stock intake, and a vector computer tune. I've considered adding a flowmaster resonator, but I'm used to the volume now.
Here's a link to the flowmaster res.
http://www.flowmastermufflers.com/pr...u cts_id=2299
I just noticed it's 3" in and out, so you'd need the venturi reducers also.