i dont have a swap myself but im thinkin about goin RB20.
from searching i learned that:
$1200 from venus, direct bolt in (with some hood and downpipe trimming) or get mounts for $350 (top hat) and you don't need to trim. add an electric fan, get the 240sx speedometer recalibrated (top hat charges $100) or hook up the rb20 cluster if you know how to.
wiring is not clear yet since nobody has done a complete walkthrough yet but from what i read you hook up your 240sx lower harness and add the RB20 upper harness somehow. id be great if someone did a walkthrough btw
dont forget about PS and A/C. these should hook up as well with some line bending and tweaking.
please correct me if im wrong.
overall i estimated about $2000 for the complete install. you can't beat an I6. theres a reason why supras and skylines have an I6
