all depends on driver. u could run a 17 or a mid-13
anyways
www.srswap.com for info
i suggest s14 engine. most likely less miles, more power, wirign problems will arise w/ s13 chassis, but can be worked out.
s15 is waste of money. you can juice out more power then it makes stock w/ a s13 redtop. s15 is more required too (driftshaft/diff, etc)