I drove the MB, 328xi, Lexus 250 and the A4 at the Audi Driving Experience. The MB was a "pig" and the worst of the bunch. Sorry. It understeered like crazy, wallowed like a small whale, was slow and had the ugliest interior.
The A4 was as good or better as the 328xi in handling but larger, more power and better interior.
Yes, we were driving 3.2's but as you have experienced, the 2.0 is no slouch. Get the A4, save up for some after market 18" wheels and use the 17's for winter tires later. You can mod out the exhaust tips - should be a simple, inexpensive fix.
One year from now, you'll be glad you did it.
Good job on getting the dealer to honor the IBM partner discount. You'll be a couple of grand ahead of most anyone else buying a new A4 this year.

2009 A4 3.2 Prestige
- Ice Silver;Nav w/backup camera; wood
2002 allroad
- Alpaca beige over ecru (ecru??)
2001 A6 2.7T (Gone....sigh..)