Hey Vin - I can kinda sorta help out...I had a 2004 B6 S4 (V8 6sp) and a 2001 A6 2.7T (V6TT 6sp) and drove a friend's 2002 S6 from time to time, so between the three I might be able to give some decent feedback.

Highs - AWESOME V8 sound/power/driveability/response/durability. Amazing amount of space with A6 Avant chassis, including loads of passenger space for four. Best smelling leather this side of a Bentley. Gorgeous interior design and layout. Best switchgear operation in the biz. Beautiful exterior architecture (easily enhanced with RS6 wheels). Luxuriously equipped. Much better space utilization (and more of it) than E39 Touring. Quattro is simply hard to beat if your drive includes non-OC weather. It eats snow and ice for lunch.

Lows - Audi dealers in general (mine was terrific, but he was the rare one). Some A6s suffer from quality issues, but in terms of the V8 drivetrain, it's pretty much bulletproof (some of the V6 TTs have issues...expensive ones at that, although in my experience both our twin-turbo V6s - the 2000 B5 S4 and the A6 - were solid). Some people complained about the Bose audio. It wasn't as good as the one in the B5 S4, which was excellent, IMO, but it was still pretty darn good. Handling best described as "wooden" and is as entertaining as mid-level Soviet bureaucrats. Not much fun at the limit with lots of understeer.

The only problems I had with my 2001 A6 2.7T were under-designed brake rotors (I had the HP2 units that were supposed to be the high-performance units, but replaced rotors approximately every 9 months). I also had an HVAC unit replaced. All under warranty. You might find Nav, but it's not the tres cool Audi NavPlus. It's the 1st gen Nav system with the knob and buttons on the center console and the arrows/directions in the IP. It works, but it ain't pretty.

Hope this helps. Overall, it's a very good car with pure luxury and semi-serious sporting aspirations. The E39 540iT would be more of a road car, to be sure, but would have less space and arguably lesser aesthetic appeal. Tough call. I love 'em both!

Mike

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