in general alloy forged pistons can slap pretty much in any engine. this is because ally forged pistons expand faster and more then cast pistons. so piston to bore clearance is generally larger to allow for the expantion when the piston heats up. "slap" should only occur when cold. many new types of pistons materials are better so you can run much tighter clearances then few years back. wossner pistons in the gt run about 0.07mm skirt clearance.