I think they look okay,
At least for the "europe styles"
It's not that they would be my favourites...but if i had too, i could live with it!!!
And like "csheriff" said: it's your car, do what YOU want
You wanna go 18" (x8j ???) on a stock GT???, With no lowered suspension???
If so...get some coilovers (or springs) first, then get the wheels, if you don't...the car WILL look like a SUV
And about the tires: get 225/40/18