BMW PE update:
The BMW PE exhaust has really come through. A couple of months later and a couple thousand miles made a great deal of difference in how it sounds. It sounds much more aggressive, has a nice throaty tone and true growl once you push the car past 4,000 RMP. Only now have I been as happy as I am with this purchase.
If anyone is/was/has been on the fence about a PE, I would say go for it. It's great!
"... but really, you just gotta ... you just gotta turn it all off, boys! You gotta turn it all off and you gotta wreck some tires! That's what M cars are all about, isn't it?"
-Chris Harris on the f80 M3