I had the magnaflow cat back system installed on my 2005 mini cooper convertible about a week ago. I am finding it way too loud on the highway. It has a nice sound at idle but once up to cruising speeds it is way too loud. There is a build in resonator in the system. Does anyone have any experience with making it quieter. Would a silencer work?

 

I never heard anyone say their Magnaflow was to loud. (That's what I love about them.) Not sure what you can do to quiet it down except pull it out and go with another brand. Make sure you check for any exhaust leaks, that may contribute to increase sounds at speed.
Good luck.

 

Sorry to hear you're finding the Magnaflow too loud

My buddy has an 02 MCS kitted out to do Targa rallying that has a Magnaflow exhaust. The car's interior is stripped with a roll cage. We have to wear pilot-type headphones with voice-activated mics if we want to chat when ferrying the car between stages as highways speeds (cruisng at roughly 3000 to 3250 RPM).

You can imagine how loud it gets when the car is being pushed hard on stages!