The guards were very close to the wheel, and when l went to roll them l found some rust....so l literally just cut about an inch off the guard.

I'm running 15" though, so l doubt you'd have any probs at all with 13". It still would have worked with the 15" if l just rolled the guards.

Oh yeah, lowering blocks are legal as long as they meet the material certification as specified by vicroads (in vic anyway). So yes you can make your own, and yes it would be really cheap.

You wouldn't want more than two inch blocks anyway, coz then it induces larger displacements and much poorer handling.