a 225 tire on a 42mm offset wheel may rub the fender a little.
I used to autox on 225 tires on a 15x7 45mm offset wheel and got a little rub. not bad, but enough to take the paint off the inner lip. and your tires would stick out 3mm more.
May 2014 ROTM, June 2015 ROTM
for auto-x: '04 Liquid Grey ZX3
for street: '02 Infrared SVT