u dont really need an engine rebuild coz like the dude said can make over 460hp with stock internals and if uve seen hi octane 4 and 3 , they go thro a whole rb26 deal and end up doin high 11's without doin a whole rebuild
but if u really wanna blow ur cash then heres how www.hioctaneracing.com.au u can find a whole engine rebuild pack for like 6 - 8 grand , sometimes having japanese parts isnt the best.....