Originally Posted by Juice420
The reason the stock muffler is so long is so that it makes the exhaust quieter. The longer or bigger the muffler the more quiet it will be. And that's the reason you don't see aftermarket mufflers that long. My recommendation for you is to swap it out with what you want as far as sound. If you want it quiet go with another o.e.m. muffler. If you want some rumble go with a 40 series Flowmaster.
Thanks gents. I think I'll go with a Flowmaster 70 (smaller than OEM).
Small follow up question: Does muffler size/type have any effect on performance (besides noise level)? I've just started looking at glass packs/cherry bombs and I'm wondering where those fit in? I know they reduce backpressure, but is volume the reason that most people don't have them?