I paid $85

There is no annoying resonance at highway speed

There is a "slight" increase in vibration due to the increase and tone of the exhaust, but it doesn't bother me. Makes it feel like the car is alive and more performance oriented.

I WOULD NOT remove the rear cats if it's you daily driver, that's going to be way loud. I started it without the rear section of the exhaust connected and it's LOUD!

It did give me an increase in seat of the pants pull at part throttle pulling through 35-55 MPH.

It sounds like a cross between a 350Z with a Cat-Back and an LS1 GTO with exhaust. It's very deep, but still has that 6 cylinder "ring" or harmony to it. Sounds very mean without being too annoying. Cruising with no load on teh engine is only about 20% louder than before. Still comfortable and doesn't drone, but you know it's there.