Everyone put your head together and think what parts and labor are needed to piece our own turbo kit.... This is what I think I will need and please add if I missed or didn't know about...and also this is on a budget so try to keep the prices down...

Silvia manifold/Bluebird manifold??
T25/T28 Turbo
Custom downpipe
Custom IC piping/plumbing
Blowoff Valve
Intercooler
Fuel Pump
Q45/300ZX Injectors
I already have an Apex AFC for tuning
maybe some type of boost controller
and can't think of anything else really...

if you are going to do this ..do it right ...first this belongs in the engine section. Second ..for which G20? Lets take it from there :)