Actually I think 40 profile is what he needs. I got new tyres on my car 2 weeks ago from John at wheels world. he recommended the 215/40R17 as they are the closest to the rolling diameter of the original wheels for GC8s. The 45 profile is suited to the GD chassis. In saying this I got the 45 profile as they worked out at a better tyre in my price range.

if you are looking for some real cheap tyres, there is a place on hector st osborne park that quoted me $135 a tyre fitted and balanced for 215/45R17.