Well, Cat SX is good handling car and I didn't have much problems with breaking parts (I basically broke 2 front wishbones after more than half year of owning this car). I've basically replaced 1 rear belt just to be sure - belt was still in ok condition and I was racing on dirt tracks where you've got more little stones than on astro so I find transmission reliable.
I belive big bores will provide good improvement over std shocks.
Some videoes from my club track
http://mkkosice.sk/index.php?option=...id=46&Itemid=1