As far as in car sound, the longer the muffler, the quieter and less drone there will be.
At the cars tail end, glass pack type mufflers will certainly help. Though use caution in your choice. Many will neckndown on the inside. This is a restriction that will hamper
HP output.

I suggest Magna Flow. The inside diameter remains the same. Nonrestrictive. You have noticed they come in 3 lengths. I installed mine past the rear axle along side the fuel tank. Here again, the longer the quieter.

I used Dyno Max Super Turbos behind a 5.9 Magnum w/Hooker Super Comp headers. (1-3/4) into a 2-1/2 exhaust. Pretty good on its own. The Magna Flows take a few more decibels out.