Good size rims???

[Bunta]

I was wondering whats a good size rim and tires?

I was thinking either 17x 8 or 8.5 , with 235/40/17

or

18x 8 or 8.5 with 235/40/18

I plan to drop the car a lot lower then everyone else thats why im wondering how wide and big can i get the rim and tire to be so that the car will have a very nice drop to it.