pretty much what he said^ the eagle/vitara combo is good to over 400hp, get ycp pistons. but the stock block should be fine at 200-250hp with a good tune. the y8's oil pump doesn't seem to be as good at the z6 so a port and shim job would be a good idea. If I were you I'd just make sure the motor is up to par, do a little to the oil pump, and throw some arp head bolts on it and call it a day. That's what we did when we rebuilt my friend's d16z6 del sol and we plan on just over 200hp.

if you do go vitara check out fjt http://fjdistributors.com/product_in...roducts_id=171 and look on ebay for the sellers automotivepr and fjtomei (fjt's ebay name) they are pretty much known on turbod as good to do business with