Get an r32 rb25de and slot an rb30 bottom end under it, then extractors, cam regrinds, head work, high comp pistons, solid lifters, valve springs. Strip off extra weight i.e. a/c, HICAS, interior, sound deadening etc. Add coil overs, locked diff, GT-R brakes, GT-R rims with street slicks, fixed back light weight seats etc. and you're set, a tough street/track machine that would take down most stock turbos.
You could pass it off as a 2ltr and race it in the 2ltr NA classes.