Can someone rate the major piston brands (JE, SRP, Arias, Ross, Probe Racing, Endyn/Wiseco) from lowest to highest silicon content (e.g. from loosest to tightest wall clearances)?? From what I've heard, Arias has fairly low silicon content, so it expands more and makes more noise than the others, but can take good abuse. How about the other brands? How do they compare in wall clearance (silicon content)? Also, Probe pistons seem to only be used by Import Builders. Anyone know anything about these? Thanks.