I'm not familiar with C-stock rules
Most of our cars are in prepared classes BSP/FP/XP
That being said.. stick with the stock bars and buy some BoxsterS bars (MO30) I typically carry with me 3-4 rear bars and just swap them out until I have a stock shocked car balanced the way I want it. The rear takes 10min to swap out.. the front takes a little longer.
Bars I go to the track with (and AutoX)
Tarrett
MO30
Stock
I believe you can backdate/update in C-stock?
B