I know you can fit 18" to an a4 but are there any rubbing problems from lock to lock?
What if the car has been lowered?
Whats the tyre wear like is it even?
I could really do with some help with these questions please.

Ash

 

people have had rubbing issues with a 235 tire I ran a 225 tire with my 18" lowered and never had any rubbing issues

 

you could have easily found this via search....

but yes, there are many people running 18's without an issue, lowered. Run 225/40/18's to be safe, tire wear will be fine if you don't lower it too much, and check your allignment if you havent had it done recently.