My exhaust is too loud?

I recently installed flowmaster super 44's on my Charger R/T, primarily for the performance enhancements. Now it is soo loud inside the car, I have to crank the radio up to drown it out. I've installed sound dampening material in the trunk and on the floors but it hasn't helped much. I really like the added Performance and EXTERIOR sound but, I also enjoy my road trips and listening to this for 8 hours or so is almost enough to drive me crazy! Any suggestions on how to make it a little quieter?