Was the $600 price from the US and not including shipping? There is no difference going from 17s to 18s cos the thinner tyres will balance out with the increase in size of rims. That ISF replica $1800 seems to be the price from Tempe, AGR, ST George Tyres etc. BUT i recon ask for better tyres, get the wheels and go to Bob Jane Granville and ask for Jeremy he will give you good tyre deal!! Ps, i'll be going there to take back my 18s i left there when i upgrade to 19s. SEE YOU THERE!!! :)