To all of you chipped 10vt guys, are any of you running a 3"? I was thinking about going with a 3" on the Coupe when the time comes, but am unsure if that's too big of a diameter.

Very little difference in flow between 3" and 2 1/2". 2 1/2 can be a lot easier to fit. After a lot of comparison, I put 2 1/2 on my minivan (same displacement, higher pressure than most Audis) and have no complaints. If you are building your own, which I did, 3" has gotten easier. A lot of diesel pickups use it, so the pre formed mandrel bends aren't too hard to find.

Dynomax Ultraflow mufflers. 2.5" in/out versions typically flow 1000cfm.

...when I do Megasquirt. That won't be for at least a couple years. Turbo motors don't necessarily need backpressure like NA motors, do they? My main concern would be going too big for now, and hurting my performance.

When considering the amount of effort or expense, it should be remembered that a 15% increase in flow does not necessarily translate to a 15% increase in power. You have to "need" the flow before it provides extremely beneficial results. I cannot do the conversion, nor provide a factor. But, it should be obvious that once an optimal size is reached further increases have only incremental results. On the other hand, if there is plenty of room for a 3", I don't know why not. But, please, don't put a "fart pipe" on it.

http://www.gusmahon.org/html/mufflers.htm<ul><li><a href="http://www.gusmahon.org/html/cooler%20test.htm">http://www.gusmahon.org/html/cooler%20test.htm</a</li></ul>

...it's just going to be raw pipe coming out the back. No tip, no nothing. Not angled, but a straight 90 degrees. I saw a WRX STi like that once, and I liked the look. It was clean and understated. Kinda 'sleeper' as well as being aggressive if you know what to look for.

Have kept my exhaust like that on the last two cars. Raw, sleeper and yet still mean!
<img src="http://www.motorgeek.com/phpBB2/download.php?id=629" border="1">