Leafy Bug
You would have to at least modify intercooler piping, and your throttle cable.
As for the computer I don't know sorry.
Maybe.... just maybe GTIR-Keiron's (comment above) 'performance mechanic' who is an RB20 guru might be able to give you some performance advice though. It really sounds like his his mate's, wife's, cousin's, roomate's, aunt knows what they are talking about.
R32_Abuser
Thanks mate I have replied to your email with some options. Perhaps if we were to go ahead with a deal we should get GTIR-Keiron's 'performance mechanic' to provide some independant consultancy services, and a complete a full compare and contast report on the efficacy of the RB20 forward facing plenum, versus the standard plenum. Sounds like he really knows his stuff.
GTIR-Keiron
Thanks for the input buddy/nay sayer. Ive sent you a PM requesting you to edit your comments. Please keep your unquantified comments out of other people's threads. Why waste everyone's time here?