I installed the Vetterman exhaust; stock it comes with two heater-mufflers. After installing the full system and putting on the bottom cowl, I wasn't happy with the amount of clearance between my engine mounts, cowl and mufflers. I've ordered a pair of muffle- free pipes to see if I can gain more clearance.
Exhaust without mufflers
Less than 1/2 inch of clearance between cowl and mounts