Is it true that i cannot add the Hotchkis rear sway (h-sport) according to the rules of H-stock?

My car already has the SS+ and Xenon lights

 

The only suspension mods for SCCA stock classes are front sway bar and shocks.

You can change out rims as long as they within 1/4 inch of stock offset, but they must be factory sizes. For the cooper 15 or 16" for the S 16 or 17".

Race compounds, cat back exhausts and I believe brake pads can be changed.

The best thing you could do is buy and read the current rule book, everything is spelled out in it.