Having had both I much prefer the drive on 17" Monzas , the 18s look superb but on our third world road network im getting sick of the bangs and crashes that transmit themselves through the car because of them.
It's the same up here, there's tons of pot holes, would have to drive like a nun if I upgraded

Sell your own wheels on which will make them cheaper
Thought of that which isn't a bad idea really

Since the tbe was mentioned I might lean towards that... though I don't have that much money for a milltek

What's the other alternatives?
Cheers