If you're trying to get a low level:
Get some Tagamet (Cimetidine) or the generic of it and take 200mg every 2 or so hours before your test. Consume a lot of caffeine and water, do as much exercise as possible, get trashed drunk the nights before. The Cimetidine will lower all of your androgens (Test, Dht, Estrogen, etc), as part of the side effect of it's nastiness, better than any drug I know of. I've done it myself and lowered my test score by around 450 if I remember right.