I have a set on my 07 m1000. It took me a while to really get them dialed in but worth it. I ride at 6000-11000ft and they work great. They definatly add power through out the power range. You do have to clutch for them. Your power range with the twins is around 7800 rpms. They also create alot of heat so be prepared for somthing melting under the hood. If you thought it was tight trying to check your plugs with a single pipe, well its damn near impossible now. All in all I like them.