RS6 turbos are the best turbo for these motors. Its been said by just about every top company out there. 034 had mentioned it. vast obviously sold the piss out of them. JHM now is getting real strong results with them. GIAC with jeff moss loved them.
adding Nitrous has always been very sucuessfull. The 10second scam artist showed us not too long ago he had it on his car. There have been several -11.5 cars with Nitrous and ko4s
what turbos is your brother using now.