Yes to all three questions, performance and power is up because of far less back pressure for the turbo to deal with remember its trying to extract the exhaust gasses as quickly as possible so the last thing it needs is restricted flow and BMW sure did a good job with that. With the sound at idle sounds much like a V8 and under acceleration I'm told it has a nice smooth note, if I regreted what I've done I would have changed it back to original but its over two years now and no regrets.