muffler selection

Sound is so subjective. I think it's best to go to a few cruises, and listen to the cars there and talk with the owners. I've found the sound clips online pretty useless, but it may be a good starting point to rule out ones you don't like. I wouldn't use a sound clip to select the one I wanted, though.

And I wouldn't cheap out here. Not that your preferred sound has to cost a lot. But the car's sound is the backdrop for the entire driving experience. If it doesn't sound the way you want, you will regret any savings.