You can get pretty reliable data by zip code at Edmunds.com...their True Market Value database.

a previous customer. Fresh off the street can mean list.

We were given a fairly good deal, they tried to dicker more on the trade-in. However, since this was the fourth vehicle we've bought from then since 2000, and the second vehicle bought since October '03 (rs6), they had better treat us well. Basically got $1500 off MSRP, plus the solar sunroof gratis, since I didn't really want it.

Was able to get $4k off and wasnt sure if I could have done better.

This response is brought to you by someone who paid list!

The best car bargain we ever made was on an old (I forget the exact year - maybe '75) Saab 99 - this was in 1987. It was on a used car lot of a large dealership - they had no idea what the car was worth. (or even what the car was.... the salesman couldn't find the ignition!) They had originally had it priced at $3800, but I had my brother check it out and it needed a new transmission. We went in and offered $800 - They politely told us we were crazy, I told them to call when they were ready to accept the offer. The salesman called us every week to see if we were ready to deal - meanwhile they kept lowering the price little-by-little. After about a month he finally called and said, Okay, Okay, you can have it for $800! It definately helps when you know the vehicle better than the salespeople. However, I don't think this tactic would have worked so well on my A8L :) Although the price got better on the last day of the month!