I would like to try a set of race tires, will this pull me out of STX, the only mods I have done are springs shocks & sway bar????

 

Race tires will put you out of STX but you could still run DSP or SM. STX and DSP mods are similar (though not 100% the same) with the obvious difference in your case of STX requiring street tires and DSP allowing Dot R tires.

Personally I recommend running whichever class has other local competitors in it, just for the fun and challenge of running against someone else. Technically, DSP would be better if you cared about trophies outside the regional level given the more extensive (much more) mods allowed in SM.

Have fun with the stickies.

Scott
90SM