I've got a RS6 in a box, which consists of all RS6 parts minus the longblock.

Included are:

intercoolers
inner fender liners
exhaust manifolds
turbos
wiring harness
ECM
intake manifold with throttle body
turbo piping
CF airbox
CF engine cover
sensors except O2
secondary airpump and lines
water lines

This would be perfect for someone wanting to convert their 4.2 to RS6 specs.