[Student Driver]

SPI's work great. Wiseco's need more clearance to cylinder wall because of more expansion. The average rider doesn't have patience to allow the engines to fully warm up evenly and take off and squeek the wiseco's.

true.

I do warm up completely before each ride, but I still won't run the Weiscos.
Being forged, they expand and contract more, and that, to me, brings on 2 issues.
1, they are more prone to piston slap when cold (before/during warm up)
2, since they expand more, it stands to reason they they will expand more if I get a little hot.

I just think that cast pistons are better for longevity.

The one reason I can see for running Weiscos is for competition.
A lighter weight, matched weight set of slugs will take less energy to move through the stroke, and thus, put that little more out. MUCH more maintenence in racing than in riding though.