Enormous fun isn't it? I have to say that given the choice between the Nurburgring or the Nokian test track in Finland I think it would be Finland every time.
Not sure which tyres you have one but if you do feel like getting a little more adventurous it's worth turning the traction control off. If the car senses quite a bit of slip it will just cut power, cut power, cut power until you're stood still. Knocking the gearbox into manual can really help too. This goes for 2WD or (Haldex on a Lexus?) 4WD.