Which power adder:

[ScottyB]

The VR-4 has two extremely small turbos, but they spool so amazingly quick that it is almost as if the car is NA (ie: virtually no lag at all).

thats pretty much the same setup and rationale as the older bi-turbo S4. it uses rather tiny KKK K04 turbos, one per each bank of it's V6. they spool up almost fully by about 2000 rpm. Most audi customers expect a smooth powerband, which is why audi chose such a small turbo for the quick spool-up.