I've ran on 215/50 and 225/50.
The 225/50 has roughly the same sidewall as the 205/55's (just a lot wider)
I ran 45 front & 42 rear. That was hot pressure. (you don't want the pressure to exceed the maximum when you are racing on them)
A good guesstimate "cold" is to drop 2 psi. Most Auto-X courses are only 45-60 seconds long. It's not like you are running open track.
If you want the tail to "dance" a little more (rear oversteer) then increase the rears closer to the fronts.
