What are you looking to get out of autox? If you're not going to run pro solo I would avoid SCCA. The bay area events are packed and you get very little time on course. I've heard good things about BMW CCA and had very good experiences with the Golden Gate Lotus club, they usually run an event every 1-2 months from April to November.
http://www.gglotus.org/ggautox/ggautox.htm
The nice thing about golden gate is they have a pretty simple classification system, you're a lotus or you're not, so everyone is pretty much just competing for top time of the day. That said, to be competitive the best mod would probably r-comps and camber plates up front, sway bars might help to reduce the amount of body roll, but in the end you won't see any greater benefit than sticky rubber.