They aren't that bad...I know of a few automatic TT Z's that are running 11-10 second times, and are still regularly driven on the street. As for why they aren't common, I would think their weight and their uncomfortable engine bays make them not too tuner friendly...but they are around.
My wife and I are both track day drivers and we have started a free online magazine catering exclusively to the track day driver enthusiast. We welcome you to visit our website at autotrackdaymonthly.com
Check out just some of our original articles:
Track designer Alan Wilson is interviewed
SCCA Colorado Rallycross
Click here to view our RallyCross Promo Video 2010
7:00 AM to 8:00 AM Course set-up
8:00 AM to 9:00 AM Registration
9:00 AM to 9:30 AM Tech inspection
9:30 AM to 9:40 AM Drivers meeting...
So for the last month or so I've been dealing with several persistent codes that have really drove me bananas and if you own the following, keep reading and hopefully this will help someone in the same situation:
2002-2006 Nissan Altima 3.5L
2002-2008 Nissan Maxima 3.5L
2004+ Nissan Quest