To my knowledge its a stock exhaust...I can tell you there is one central resonator and each outlet from there has 2 mufflers on each side. At idle on the outside you would almost never know its a v8, you just get a bit of pleasant resonanace on the inside with the windows open.

Supercharger whine, its very unobtrusive, which I prefer...I hate the whine from a supercharger myself so if I could never hear it again it'd be ok by me...Dodge Hellcats and kids putting aftermarket pullys on Audis have ruined that for me though...those things are all whine and no motor sound. I wish mine didn't make the supercharger noise when I'm cruising along on the highway at 75-80, but its not too bad, radio covers it up nicely...I knew there were risks to buying a supercharged car so its all good, its prety muted.

 

I had similar issues with the Porsche 944. It also had the BBS wheels and would give a steering wheel
wobble at 50 mph then smooth out until a little over 70. It turned out that I had a wheel out of round and
another out of balance. One of the stick-on wheel weights had come off.