Looking to get new tyre's soon.

I want to address the issue where my rims are so easy to damage. If i touch a kerb, I will almost certainly damage my rims. The lip of the rim is exposed.

I currently run 225x40x18 on 8.5inch rim.

So, If I go 235x40x18, this should short it out? I am pretty low and scrub a little bit on the liners when pushing the car hard into corners, so not to keen on going 245, but would probably look pretty good?

Also, should one stick with a 40 profile, or goto 45?

Tyre recommendations based on the above? I am running Nitto Invo's currently and have been REALLY REALLY impressed by these tyres.