Joe ///M: To me, modifying these cars is frustrating. . .it makes me want to revert back to buying cars from the pre-emission control era when we had more control over engine tuning. No, I wouldn't just add a free-flow exhaust without also installing a matched chip. (That's why I mentioned Dinan; they have both.) Does B&B sell or otherwise recommend a chip for their system? If not, I'd probably steer clear-despite the fact that they look great under the car. By the way, from what I understand the stock M6 muffler is already fairly unrestricted so adding an aftermarket muffler of any kind might be a waste of $$$ in your case. I believe an offset cam sprocket is supposed to be more cost-effective modification on the M6. I hope this helps. Larry