We installed the cat-back today and immediately engaged in some "spirited" driving. Inside the car, there is a definite tone difference, but not annoying a bit. Throttle response is significantly improved.
Outside the car at start up, the exhaust provides a nice, deep tone. Outside during acceleration and deceleration is a huge difference from stock. We heard no rasp, no popping, nothing high pitched. The car presents you with an aggressive, clean sound. I will see if it sets off car alarms in parking garages like the exhaust on my 71 240.
I waited 8 weeks and had researched almost every one of the available systems before going with Berk. In my opinion, I made the absolutely correct move.
Oh yeah -- installation (in my garage) took me and one of my sons 2 hours 15 minutes. It would have been much less but we wrestled with a reluctant nut of a bit.
Here is a link to some pictures:
Nissan 370Z Forum - onzedge's Album: Berk CBS Install