I never raced a regular 3 series but a brand new m3 spanked me in my mustang about a month ago. I dont wanna sound like a ricer but your best bet with the subie will be from a roll. Off the line AWD will own you, he has the option of dumping the clutch and slingshotting out of the hole while you vaporize tires.
Win or lose don't sweat it, anyone who races on a fairly regular basis loses sometimes or they are lying about it.