RE-11s are good too. Be aware that you'll heat cycle your PSS out pretty quickly as you track them, and towards the end of their life breakaway gets far more abrupt, exactly what you're trying to avoid.
You might read through this thread if you haven't seen it, I suspect you may have been caught out by a similar issue:
http://www.1addicts.com/forums/showthread.php?t=1003523
Also be aware that you can upgrade to euro MDM coding for about $100- it allows a little more slip, if the stock MDM is bugging you.
Final thought- understeer/ oversteer on a staggered or square setup is very tire dependent. Dunlop Sport Maxx Race in stock sizes understeer terribly staggered, even with camber plates up front. Pilot Sport Cup 2s, on the other hand, are very neutral, nearly ideally balanced for lap time. YMMV.