Looking for max performance summer tires that rival the strength the venerable S0-3's. Not interested in the F1-GSD3's either BTW...

TIA

soft compared to either.

In your size the Michelin PS2 would be the stiffest we know of.

RE01-R, Yoko Advan Neova and BFG KD are a bit stiffer, but not available in the size you're after.<ul><li><a href="http://www.tirerack.com/a.jsp?a=AR8&amp;url=/tires/index.jsp">Tires</a></li></ul>