I have the S&B... I love it. Again, performance gains??? Probably not. I accompanied the purchase of the CAI with SPD turbo adapters, catted down pipes, SVC intercooler, and a tune from Goosetuned. So yeah, this thing rips! S&B has awesome customer service. My clear plastic box cover was a little off in fitment, and they sent me 3 more with the rubber seals to ensure I was happy and the fit was tighter, no questions asked.
Edit: I can definitely hear the turbo whine way better... CAI alone?? Again, probably not.