I have Berk HFC and CBE. I bought it for the performance gains, everything else was a bonus.
Pros-
- Proven performance gains
- Wicked sound
- Nice fit and finish
- Top notch customer service
Cons-
- There is a bit of rasp from the HFC when letting off the throttle at low ~2000 RPM
Like I said, I bought if for the performance gains. The very slight rasp (from the HFC only) doesn't bother me but I added it as a con because that does tend to bother people on this forum.