I look at it this way: I'm going to take a vacation this year anyway. I'm going to buy a new car anyway. The amount saved between the ED price and what I would pay for a car off the lot will cover airfare and hotels (if you consider the difference from MSRP it would be a lot more, but who pays MSRP?). Now I just pay for food, gas, and other vacation related expenses. I come out ahead in terms of cost.
Cost aside, what other vacation will give me the opportunity to drive a brand new M3 through the Alps, Italian Lakes, Black Forest, and the on the Nurburgring? And within a couple of months I'll have that same M3 in my garage.
September 20th can't get here soon enough.