Alignment has nothin to do with treadwear if it is even treadwear. Alignment can explain uneven wear or wear on outer or inner parts of the tire but a normal wear pattern has nothing to do with alignment.
If you are in really hot weather and even driving moderatly you are still putting down 300-400hp crank which is a lot more than the audi and tires go quickly. Most get 6k-8k if they drive relatively agressively so you are on target for about 8k which is pretty standard. Unfortunately it is the price of admission along with the crap gas mileage etc. Pay to play even for an m3 which itself is not overly expensive. Kind of like a big house. You can get in the door but dont underestimate the increased cost of maintence, cooling/heating, yard work, water etc. Pay to play