I was thinking about getting a DG main pipe as I already have their type II silencer. I called DG and asked what is the difference between the 2 pipes the offer. The xtreme and the national. He said it was just the finish. One is nickel and the other is raw. I was wondering if any of you knew if there was a performance difference. Or, if there is another brand of exhaust I should go with that is better. Thanks, Daron