@ray.a - Offset, in addition to wheel width, is an important factor that needs to be considered when changing wheels - if the new wheels you’re considering have quite an aggressive offset, then there’s a potential risk of tyre rubbing issues, especially as you’re moving up from a 7.5J to 8.5J wheel. You can check to see if you’re likely to have any clearance / rubbing issues by using a calculator such as the one on
www.willtheyfit.com.
Presumably, your current tyres are 225/40 R18. If so, moving to an 8.5J wheel will increase the risk of damage to the rim of your new wheels as the tyres will provide much less - or no - protection to the rim of the wheel against kerbing damage.