Is there a good performance muffler that's quiet?

I currently have a single 2-chambered Flowmaster (3" in/out) dumped under the bed right in front of the axle on my 04' Dodge Ram 1500 Hemi quad cab. For driving around town, and even on the highway it sounds awesome......nice deep idle, pretty quiet when cruising on the highway, and really screams when you mash the pedal. I tow a 25ft ski boat with my truck, and short trips to the lake (1 hour) don't really bother me too much, but the exhaust can get a little loud at times when you starting getting into the gas going up hills.

Now that we picked up a small 19ft camper trailer, and I've been going on some longer road trips with the family......and after a few hours, the exhaust note just gets annoying. It's not bad when you are on flat ground, but going up hills when the motor is spinning higher rpms just gets annoying.....I'm tired of hearing it (so are the wife and kid).

I'm going to cut the Flowmaster off and replace it with something else. I don't want to lose any power, but I do want to lose the noise and interior resonance. What should I try? Magnaflow? Borla? I want something that's quiet.....something that won't get annoying after pulling a trailer for 6+ hours.