I'm pretty sure there was a post with dyno results with berk awhile back before the 2 group buys. Not sure where they are to dig it up though.. let me look
DDMotorsports: Berk Technology Cat-Back Exhaust
Here is the dyno results. Baseline is with berk hfc and then catback is added on the next dyno.
baseline(with hfc)
1:280.80hp 244.28tq
2:284.15hp 243.22tq
3:281.29hp 248.50tq
cbe with hfc
296.90hp 250.91tq