I got an F10 M5 exhaust, which I plan to install onto my F10 535i. I know that the quad tips don't fit on a stock bumper, so I plan to get a M5 style rear bumper off ebay (https://goo.gl/k5oCmf). I've read on several posts that the ebay seller is reputable and delivers a quality product.

Anyway, this is for all my OC/LA members. I wanted to know which muffler shops would you recommend that I take my car in to install the M5 mufflers. Also, I've read some members wiring the vales to keep them open on the M5 mufflers. Is that for more for noise control? Are there any negative effects leaving the valves as is on my 535i?

Thanks!