Ok this may sound unusual but has anyone tried to modify the 6th gen exhaust from under the seat to the older style side mount? I was thinking this might relieve some of the heat on the back of the legs. I know the "two brothers" systems route it to one can anyway.
I'v never had a problem with the passenger complaining of heat off the exhaust (with just a factory exhaust system). I can not speak for any other type of exhaust.
I've heard of some people modifying a 5th gen, low mount to fit on a 6th gen. Are you or your passenger uncomfortable with the heat? I've done thousands of miles with a passenger and with the saddle bags. Never any discomfort. You could always opt for an after market or smaller muffler that would not hold as much heat as the big factory mufflers.
