About to order my shorty exhaust. Anyone install one of these before?

same as installing any other slip on besides the plate

You could actually remove the factory muffler and ride the R3 like that--I did. The catalytic converter is the back pressure regulator, not the tractor muffler Yamaha stuck on the bike. The one ride I did without the muffler made the bike sound like crap, so my new slip-on from Devil Evolution is on the way. I looked at the Coffman muffler as well, but did not like the black finish. I did like the fact that you do not need to connect a bracket, but you do need to drill for rivets to keep it from rotating around the pipe.
I also liked the included filler piece for the opening left in the body panel from getting rid of the factory muffler. In the end, though, I liked the polished finish and design of the Devil Evo muffler, and it's "high exit", which is even cooler. Google search "devil evolution D5M slip-on muffler for Yamaha R3"