exhaust before axle
 

I am thinking about routing my exhaust out the side before the axle. I am also getting a new muffler. Could I put the new muffler closer to the cats?

You can put it closer but you will get more drone that way.

When you say drone do you mean louder

Louder inside the cab, yes.

And he also means, a "humming" sound say at highway speeds or a specific speed. It can be annoying.

Yes, drone. Its the "resonate" frequency that reverberates inside the cab, usually at cruising speed. Very annoying. The muffler is already close to the cab, moving it farther forward would place it directly under the cab. I would speculate the drone will pretty soon drive you crazy. Might depend on your muffler of choice though. My experience with flowmaster is lots of drone, my magnaflow still had some drone but is was quieter in the cab.

My current muffler is a jba (I think it was on the truck when I bought it.) It already has a bit of drone. The new muffler is a flowmaster super 44. Would 4 inches even make a noticable difference?

One more thing to think about, that rear wheel behind the pipe will be a pita to keep clean. No matter how good your motor runs it will discolour that one wheel. Ask me how I know.

I had a flowmaster super 44. It was loud in the cab. Too loud.

I was my truck at least once a week. Should be enough to keep thet wheel clean