so.... if ur running a gt gbox consider 22x8x13s first... if u see that ur not getting enough grip though the run then switch to 23x8x13s
if ur running a glanza gbox i would suggest 23x8x13s in any case if ur running over 300bhp, as they really help
**edit** just noticed... so 22s & 23s will fit without any problem on a 13x7.5 rim.. with an offset of 23..
but ull need to raise the car quite alot to run 23s.. they are very similar to running 205x40x16s ... except about half an inch bigger (diameter wise).
kon