I have an 08' m1000 that is stock. I just installed an aftermarket muffler. It starts and idles fine but loads up in the midrange and bogs out. If you blip the throttle 5-10 times it will clear up for a bit and then do it again. The muffler is speedwerx can. With an infrared temp gauage the y-pipe only reads 500-600f. I believe it should be around 800. I was told that its a bolt on item.