[What OFFSET?] 18z on 99 Vectra?

[Akeemking]

Hi there
one of my m8z is getting 18z for his Vectra state
but i dont know if the ET49 is the best for this wheels
and what size/width is better for wheel and tyre on his car/state

(5x110)

The sizes available:
7.5 x 18"
8.5 x 18"

Kosei RZ:



Please help us here!

Thankz

[lee may]

7 1/2 x 18 ET 45 with 215/35/18 tyres.

Might just get away with 215/40/18 if not lowered too much