If you're really worried, some of the local companies do demo laps for you to show the 'gotchas'...to point out the turn-in and apex points, the off camber corners and where the car is most likely to get out of shape...
Try these guys, they are super helpful, and professional (just email / call to ask if they can take you out on a demo/safety lap, as opposed to hiring a car):
http://rentracecar.de/index-gb.htm