On my 2001 Grand Prix GTP, I had SLP headers and the SLP exhaust system. No resonator and it droned badly at highway speed. It got on my nerves. Didn't sound that good either. In my opinion, a 6 cylinder will never sound as good as a V8. Having said that, I would like to hear a Corsa system on a w-body. Bet it sounds the best you are going to get.Good to know. What helped you come to that conclusion? Did you try something?