Rekin I'm one of the lucky ones. The kid that does exhaust work at one of the local tire shops is GOOD. All I need to tell him is the basics of what I'm looking for ... he corrects me on a few minor details ... I come back in 4 hours to an installed muffler.

Scott - you shouldn't have to worry about the tail pipe. Walk in with the muffler of choice & they should be able to take care of the rest.

As far as back pressure - that's just the amount of force required to push the exhaust through the entire exhaust system. It's not a number that they typically publish but more of a general statement if the muffler was designed to minimize it.