Yeah, that's what I've been thinking. Make sure it'd *REALLY* make a big difference in your situation to sell it before you do anything you may regret. I'd do a lot of number crunching before making up my mind.
On the Audis with the 4.2 V8, while the V8 S4s seem to be OK, the previous generation A6/S6 and A8/S8 (post model year 2000) have some *very* significant issues with the drive-by-wire. I've had or driven quite a few of these, and can count the good ones on one hand. And no, my S8 isn't one of them, though it's better than the other S8s I've been around. I'd be *very* leery of buying a used Audi with a V8, I'd figure that d-b-w issues are why it's on the used car market. And no, there's no fix. Even swapping computers/etc. doesn't fix it. After driving a M3, the Audi throttle response would drive you crazy if you got a bad one.