>>the mufflers are quite far forward,<<
I reread this thread and could not find where you mentioned what is after the muffler. How far do the pipes extend and where do they exit?
The quietest mufflers you can find, will be loud and raspy if bolted directly to headers or mounted close to exhaust manifold and there is no tail pipe after the muffler. Exiting under the bed, turns the bed into a vibrating megaphone.
