I received you pm and wanted to comment quickly about the settings. I have not read the entire thread yet due to lack of time... I will be back in posting action in a month or so...
Your settings are going to be much different for track racing compared to my "strictly autocross" setup. I know our cars can oversteer but many times our cars are over-driven and pushed into understeer. For track racing I'd rather have understeer rather than push the envelope of oversteer.
Also each car will react differently to springs depending on what else you have done. Roll centers, CG height, tire width, pressures, shock settings will all play major roll in spring stiffness decisions.For a stock RC and slightly lowered CG I'd stick with something like 550 lb springs up front and about 350 or 400 in the rear for autocross, for track I'd go with a slightly lower rear spring and stiffer front bar. This will all depend on your rear bar, settings also... Testing, testing ad more testing is the answer... and don;t forget to tune for your particular driving style, this is what many people forget. :wink: