indeed it is a beast!

 

Performance parts are not cheap.

Good performance parts for Audi are even more expensive.

Audi Performance =$$$$$$$$$$$$

 

I think those gains in the first post are way too optimistic.

400WHP on a Mustang -> 590 HP at the Flywheel?

Rather too optimistic. You're playing with multiplying factors, when the only real value is the WHP on that dyno.

By judging on the 400WHP on the Mustang, the power loss on that dyno should be close to 50%. I find that hard to believe.

 

APR claims 590 crank HP
http://www.goapr.com/products/stage3_b7_rs4.html

The calculations are not unreasonable. 400whp on our mustang dyno is 472 dynojet whp. Factor drive train loss in and you get an estimated 590 crank HP. A Subaru sti or Evo has roughly a 20% drive train loss through the Awd system, and the Audi definitely has more loss
To know 100% engine hp the engine would have to be on a engine dyno. Once again Im not out to play a numbers game, Im simply showing a modification to a car and the gains it produced.

 

Get a Maha dyno for better results.

Also, you're still playing with factors. Factor in drive loss at 400WHP and you're at close to 50%. Realistic?