Hi. I'm assuming you've a BK 3 MPS running OEM wheels....225/45R18 are a good fit to OEM rims and won't rub on the body. I had the same size with OEM wheels (18x7+52.5) and Enkei RPFR1 (18x7.5+48) and never a problem with OEM wheels. I'd expect the same with OEM wheels on 6.
With the enkei at +48 offset needed a gentle guard roll to keep them off the guards in all circumstances however it was exceptionally rare for them to touch. The circumstance I remember they did was mid corner with a nudge at the inside rear by driving over a rock large enough to make a bump.
"Blue Meanie" 2007 Aurora Blue MPS 3 - 18x8.5+44 SSR GTX01 - 235/40R18 Michelin PS5 - 3.5" ETS TMIC - CPE stg 2 mount - HKS/CPE BPV - 2XS inlet - 2XS short shift - Corksport turbo manifold - HT 98 octane tune - Leather/Aluminium handbrake - Momo shifty knob - 7" touchscreen - JDM Mazda Retractable dashtop screen assembly - Bespoke Raspberry Pi Android based GPS/Carplay and instrumentation - 36AH reserve battery and C-TEK isolator - TEIN Street Advanced coilovers 1" drop - Superpro bushings - 220Kw/410Nm.
"Lipstick" 2013 Velocity Red MPS 3 - 18x7.5+48 Enkei RPF1 -225/40R18 Federal RS-RR - CPE TMIC - COBB inlet - CPE stg 2 mount - COBB Stage 1 98 octane tune - COBB shifty knob - 2XS short shift - 2XS turbo manifold.