Jefferson Circuit is a nice little track. I've been there a total of 3 days. It is VERY hard on brakes. Because of its very short length (1.2 miles?) and because it has several fairly hard braking zones (back straight, front straight, side straight), your brakes don't get much chance to cool. It's not a very dangerous track, but it is quite technical, especially when run in the counter-clockwise direction. If you plan on attending Hyper-Drive or any of the track sessions, make sure that you've converted your car to something like Castrol GT LMA brake fluid, and that you're running a mild upgrade sport brake pad, perhaps an Axxis metal master. The stock pads are OK but if you're using sticky rubber (I was using R compounds) you can end up overwhelming the pads a little bit.
Brake hard and late and you'll be fine <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt='

'>