The chassis setup between the two is nearly identical for STX or STR, IME.
I've got 6k/9k springs, running the Karcepts front bar (the bigger one) around the middle (lower on asphalt, higher on concrete) and a little bit of positive rake (hub to fender)
-4.9 front camber, -2.5 rear camber. Zero front toe, ~3/16" total rear toe-in.
Running equal spring rates all around is just... not ideal. You then need a really small front bar or a big rear bar to make it work well. The math supports the idea of running more rear spring, motion ratios are a thing
