I am looking to change the exhaust on my 2005 Cooper S however I want a new exhaust that will provide a boost in power without to much noise associated with it. Any recommendations on OEM product I can use here?

 

Milltek is probably the best/quiet exhaust. That's what I have and I like it alot.
Do a search for MINI and Milltek on YouTube and you will find some videos so that you can hear what it sounds like.

Another option is to perform the one-ball mod on the stock exhaust. Basically you get a muffler shop to remove the passenger side resonator. It will cost you $75-$100 to have this done. I had this mod for a while before I bought the Milltek.

Use the search function on the forum and you'll find alot of info on both exhausts.

 

I agree. I bought the Miltek and got a nice power boost with only a slight increase in volume.

 

Sounds like what I am looking for. Thanks