I use PurOl 10w40. Ive been using this for almost 2 years in both my 135 weekend car and just even just started using this oil in my DD A3. the oil is great, noticed lower oil temps and with the stock cooling ive yet to see the oil go past 270 on the track. I've also never had limp mode or anything while running this oil. It cools down fairly quickly between sessions and I've noticed the car runs much better and smoother, although my motor did blow (over 30 track days, 300-400 1st - 5th gear pulls, and 125k. i literally drove my car like i stole it but i own it). I will be using PurOl in the next motor and doing some other things to keep the car running consistently and safely. many of my friends with E30s started using it with nothing but great things to say.
http://www.bisimoto.com i normally order 2 cases at a time and its good for 3 oil changes. i change it every 4-5k or depending on how many track days ive done