I've got a polo mk3 gt and its on 13x7 revolutions front and back, at the front it sticks out the arch a little. was wondering how low should i take it, been looking at 60/40 on a g40 on standard 13" bbs and still looks as thou it could go more but dont wanna do any damage to arch. (not bothered about a bit of scrubbin).

I'd go 80/60. Wont scrub at the front, as long as your running 175 50 or 195 45s