I have purchased 6mm ones - It is very low, but the wheels are only 15" so should be fine. Just that I stiull can't work out were the rubbing noise is coming from on the offside front - but when I remove the wheel the inside of the tyre is a little shiney - which makes me think it may be rubbing on the strut slightly - strut ain't been touched though so very weird - had everything on the front changed too, rubbers, wishbones the full monty. Ah well fingers crossed eh!
Have been told that all is well - but it is more of an annoying noise..