witch one to get

Be it true duals, X or H piped first, end the muffler with enuff room for the pipe you intend to use. Example, 90* bend or 45* bend and tips, if you add them.

Muffler choice is a ***** to choose from. If your looking for suggestions on a muffler, just for the mean sound, then I think I'd go look at a Dyno Max muffler. But even a cheap muffler will do it.