Now compare that to a 2003 RS6 with a curb weight of 4229 lbs. It's kind of disturbing a chassis can gain 800 lbs. like that, and it really makes me wonder about why the RS6's handling is so porky.

 

I did some research:
03 A6 3.0 CVT FWD - 3516 lbs
03 A6 3.0 Quattro - 3516 lbs (um is this right?)
03 A6 2.7T - 3759 lbs (turbos add 243 lbs)
03 A6 4.2 - 4024 lbs (bigger engine/tranny)

Therefore a 4.2 with turbos might weigh 4024 + 243 = 4267 lbs which is just over the actual weight. I know this is unscientific but really a RS6 is not that much porkier than a straight 4.2 quattro.

By way of comparison a M5 is 4024 lbs with no AWD.

The real test is in the drivability. I think the C&D comparison speaks for itself.

 

they have always been a little porky in the current generation, and handle like a boat. i am very pleased with the s6 stock power and handling. at least it takes alot to get the beast to lean. feels the most like a rwd car of any audi i've own in 20 years of continuous quattros...
i am remined of this love for rwd sports cars,about this time each year when i switch over to the rx7 topless...rwd, no abs, no airbag, no obd1 or obd2, no esp or drive buy wire, no pistons, cylinders or valves for that matter. it was one of the first cars with built in cd/radio/compact disc players as a unit. speaker in headrests and entire system still works like new...only 150 hp from a 1.3 liter mid/front engine with 50/50 weight distribution. sticks like gule with very predictable oversteer-tail fun at the limit. loves to be reved up to 7000. takes about 3 minutes to reach full running temp. 0-60 is a blazing 8.5...little faster is you toast the clutch...
15 years with original owner and still on first brake set (>50% left on pads).used up one cluth and 2 sets of tires in 15 years... all scheduled service and lots of extra lubes, but still only spent about 3800$ on all service in last 15 years.no recalls and one electrical issue during warranty period. first hard/soft top convert with a targa option and first convert with a windblocker that really works better than any of the current versions. never driven in winter but friends with them just put on the snow tires and head to the ski slopes, handle fine...
mazda did a good job making a cheep reliable japanese porsche. imho. only a few 1000s were made for 3 years. many people paid 2-5000 above sticker. my most expensive car at the time with a purchase below sticker at 24,000$-i shook when in did the paper work. made it all much easier to do the m5 deal later in the same year for a tad more...
cheers

 

...and the 4.2 is porky! Turbos, intercoolers and associated plumbing weigh no more than about 50 lbs. on the 2.7T. That 3.0 quattro figure is too low. Realistically, Audi should easily be able to build an RS6 that is within 150 lbs. of what an A6 2.7T weighs. The 4.2 motor in the new S4 weighs the exact same as the 2.7T motor. Slap on 50 lbs. for turbos, etc., and then 100 lbs. around the car for beefier components, and you should have an RS6.