Here is my plan:
- upgraded turbos (custom RS6 based, billet compressor); high torque. Fully spooled at 3k rpm (22 psi to redline; see below).
- injectors
- downpipes
- cat back
- custom tune (maintaining N75 boost control, and will live with the stock MAP limit of 22 psi). 7200 rpm redline.
- TCU tune
- tranny valve block refresh; possibly higher line pressure solenoid

Concern:
a) should I upgrade the stock torque converter?
b) how much torque can the tranny handle?
c) added cooling capacity for trans fluid? (forgot, but assume standard Audi setup with tranny cooler incorporated into radiator).
d) Intake Air Temperature: for cosmetic reasons, FMIC may not be a good option. Stock IC are tiny. Commercially available upgraded once don't really do that much and cost a fortune. Water/meth the smarter way to go? Or can the stock IC handle 600-650 cHP?
e) I normal put upgraded motor, tranny and snub mounts in (2.7T). Similar for the RS6?

Other bottlenecks, upgrades I should consider with the engine/tranny out?