So my factory cat finally died last week at 68k miles and I replaced it with a 3" dia. high flow cat. The car feels much more responsive, but the drone from my 6-year old "Isley special" Borla exhaust is a bit too much for me for a street driven car.

I ordered a 3" Flowmaster Hushpower muffler yesterday based on a recommendation from the guys at Vorshlag, and I'm going to replace the current crush bent axle-back piping on my car. My question os this - should I build the new exhaust out of all 3" tubing, or neck it down to a smaller diameter?

 

Anyone? Anyone? Bueller? C'mon, not even Team has chimed in on this? I expected a multi-paragraph dissertation on exhaust tubing selection by this point.

 

Use 3 inch.

 

What the hell do I know. I was recently chastised for adding 40 lbs to the right rear even though my car with this weight added was still lighter than his or anyone elses STX RX-8, weight balance be damned ....