I started my car up this morning for the first time in a week, and she shot out a nice puff of blue smoke right away. No big deal really, doesn't bother me. You should see the cloud of crap that comes out of the exhaust of the Talon at WOT. With as much boost as I run on huge injectors with a rich air/fuel ratio there's lots of grey smoke (unburnt gas) that comes out. So much so that I can see it in the headlights of the car I'm smoking (literally) behind me...
It's all just part of the fun...
http://www.etdracing.com/jim/backfire.wmv
Here's a nice example at the track. I hit the rev limiter at the top of 2nd here by accident. Sounds like a shot gun lol...