i did a search on running tire sizes and found this from a poster:

Don't overthink the tire balance. Ultimately, the tire choices being discussed are close enough that it really depends on driver style preference. So, here is my humble opinion on tire selection setup for your rims.
205/245, stock suspension -> tends to understeer (SLIGHTLY safer setup for novices)
215/245, stock suspension -> close to stock balance
225/245, stock suspension -> tends to oversteer (add stiffer front anti-rollbar to dial out oversteer, a typical autoX setup)
225/255, stock suspension -> close to stock balance (probably rub on your offsets)
--> if want a lot more grip use another set of rims and R-compound tires for the track



I plan on running 225/245, what's a good front anti-rollbar to get on stock suspension?

 

225/255 with standard s2k wheel offsets dont rub.