Having a drone in my exhaust system, I decided to replace both mufflers.
I had them replaced with a pair of Walker quiet flows. The result was
mixed. The drone is gone, but I have to say it's little quieter, but still
loud when you get on it. I am not going to fool with it any more.
I guess it's the nature of the beast.

 

Does your exhaust go all the way to the back? It can be especially bad if the pipes end under the axle As you said it is the nature of the beast

 

They go straight out the back.

 

a loud exhaust can be fixed by making the last 2-3 inches necked by 20-30 % of full dia.

 

Add a resonator, most of all the box style walkers and flowmasters have that roar.. I found that a sonic turbo does not do that.

 

No room to put one on.

 

An "X" pipe before the mufflers may help.