I just purchased a 2004 Cooper S with relatively low miles, and I’m planning to install a 15% pulley kit and a performance exhaust. Any tips on the best quality brand of pulley kit? M7, CravenSpeed, Alta, etc.?? Also, I’d like an exhaust that’s louder than stock and flows better, but without droning in the cabin. I’ve had Borla exhausts on my R56’s and loved them, but they have different options for an R53. Any suggestions on what brand of exhaust to use?

 

For a pulley kit we have the perfect one as it has all that you need to do it right, and reliable.
https://www.waymotorworks.com/wmw-pulley-package.html

For exhaust we would recommend the Milltek as the res version doesn't drone and they make the most torque gains.
https://www.waymotorworks.com/millte...w-exhaust.html

The borla sounds good and fits well, but every one of them we have seen ends up cracking and leaking so we avoid them. They do have a warranty, but takes some work to get it done.