If you have the money to buy an RS6 why not just do it? I have yet to read about someone building up an allroad past the k04 stage. They seem to have torque converter problems at stage 3+. The manual is the only tranny I've read about that handles anything past 450 hp or so. The RS6 probably would, but good luck sourcing just that tranny.

besides... why do you want a DD with around 500 hp? Maybe its just me but if I was going to spend that kind of money on a car I wouldn't want to let knuckle heads bang it up in the parking lot or waste the gas at every stop light.

 

Moved over to the other forum for some good reading. LOTS of Stage 3+ Allroads there (stroked 3.0, 2.8 heads, TiAL 770).

Torque assumed from your hp seem to be in line. RS6 tranny considered good for 800 Nm (ca. 600 lbft); still trying to find out what TC is used and/or if there are any more differences to the Allroad or A6 tranny.

One reason for NOT RS6: there is no Avant in the US! Checked prices in Germany: unreal. Checked getting them licensed here: not possible.

But as it currently stands:
- RS6 Sedan plus power/turbo (K24+, likely custom built from TurboConcepts) upgrade to stay under 800 Nm torque from 3000 to 5500 RPM. Easy at lower RPM for DD (and to protect the trans and drivetrain)
- Allroad 2.7T manual, lower, wider, paint; 500 whp
- Allroad 2.7T auto, 450 lbft (RS4+ stage), lower, wider, paint
402 lowering with VAGcom initially for Allroads, but coilovers once wheels, tire, brakes are done.


As to logic: All the above can be done for $30,000. Believe it or not: there are people who spent that or more for an SUV, or a minivan, or a Ford Fusion. They must be nuts. Go figure.

 

When I started to look into RS6, i checked parts availability and prices. To my surprise, I found an engine ($4500) and a trans ($2500) right away. The regular 4.2 is not much different (heck, I paid almost 1k for my CJP for the 2.8).

Salvage RS6 are certainly hard fought for, but can be found in the 10-15k range (lucky find).

 

shoot if you can find an RS6 engine for that price pick it up and pop it in something. A pair of RS6 turbos that fit the 2.7 run around 3500$ anyway. If you did get that engine it would fit in a a6 4.2, that might be a good route to go if you can find one with a blown motor for a decent price.

As for people who buy new cars... I don't get it. I like used cars because I don't suck up all the depreciation. It might be because I'm young and have yet to find a nicely paying career, but I don't know if I could ever just throw money out the window like that.