well what kind porting you getting done? and what pipe you going with and reeds? after you figure those out then you can bump up to a bbk and really wake it up. i say replace the vitos piston because of the fact i have heard from alot of people that with there bbk's the openings on the skirt dont line up properly with there pistons. so alot of people go with the weisco piston. but if i was you id get all the stuff done but the bbk. then ride it and see if that satisfys your needs, then if not go with the big bore kit.