I've just rebuilt my rb26 last year mate, using 2530's with forged pistons and n1 gear works great and capable to make over 500rwhp
check my threads iv made alot of info there in the wa section
id budget around 10-15grand for decent gtr built, the crank is 1200, ecu 1500, clutch 2k, theres 4700 on 3 bits