I've a 2006 VRSCR and did the initial drillings myself, started small and went all the way in stages, each sounding more and more like an air cooled hog. Finally took courage and a couple of hole saws in hand (drill actually) and removed the baffles entirely. I wouldn't say there was any noticable effect on performance, but the sound at high revs was amazing (a definite head turner). Measured the output at 5000 rpm @ 1 metre as 127 decibels.
Brilliant for announcing your presence on the road to both pedestrians and white van drivers, the only downside is no-one will ride behind you it gets unconfortable above 3000 revs. but to hear it flat out is orgasmic. still hits the rev limiter in all gears, top speed (indicated) is 235/240kph I ride in 30-45 degrees centigrade, bike has never overheated or had any problems, other than the norm (Head bearing loosening and exhaust trim bolts vibrating loose) All in all, a cracking ride and so pretty.
Power Commander and K&N Filter only other mods required.
Other mods Chrome & trim, Seat, Detachable Screen and Panniers for the occassions when I get the other Lady in my life on the back.
Will be taking with me to France at the end of this contract. Its a Canadian Spec bike and if anyone knows what needs to be changed out for euronorm type approval, I'd appreciate any advice posted in response