exhaust questions

As of right now I have flow master 40 series mufflers on my duster and the drone has taken its toll on me. They sound bad *** at full throttle. And at idle but I can't hear my self think Sometimes .These are on my 410 stroker .my 1st question is what's an ALTERNATIVE MUFFLER THAT FLOWS WELL AND HAS VERY GOOD SOUND???. And my second thing is I have 3inch x pipe on the car dumped at the axle. Would exiting pipes all the way out the back be possible w/ 3inch? And is there any hp loss when doing this . . Thanks guys

I built 600 horse 92 g m c short wide, had the exh. ran from my flowmaster(3") out to behind the rear wheels like some of the older camaros had. the minute I started it to back it out of the muffler mans stall, I could feel the diff. could really tell it when I got in it, made about 3/10`s diff. needless to say, I pulled them off, dumped the exh. straight:coffee2: out w/ long turn 90`s pointed at the ground in front of the rear tires.
I still have the dual tailpipes I pulled off in the barn,if anyone wants them!
sellum cheap plus freight.-----------------------------bob