My suggestion is 225/45R18 on 18x7.5+48.
No gaurd rolling really necessary with most domestic tyres, but go for Kumho KU-36 Or Falken RT-615 and you should - I had to.
225/40 also fit to same wheel and won't need the roll, but you'll have even crapper speedo accuracy (thinking 3). Most people don't seem to care.
I wouldn't go 245. If you want wider than 225, I'd be picking 18x8+48 and fit 235/40R18. Common falcodore tyre size which = good pricing.
If you really want to go wider than that, be sure to get a high offset of +48 or more (+52.5 max)and 8.5" wide wheels.
I'm conservative about this. I would not be comfortable with such an aggressive fitment width.
+45 8.5" wide would be asking for a canary around here, I think.
Copper had a good hard look at my guards last time I was checked.
Other thing to remember is where your inside track sits. If the inside track sits further inwards, steering gets heavier. inside track sits further out, steering gets lighter with more negative feedback. Function of offset. +48 with 225 tyres places the inside track within 0.5mm of the stock position, for all intents and purposes the steering and feedback is stock feel.
"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.