Go for 215's i did.
I have 215/55/16 Avon m500 they are great-HOWEVER- i have noticed that the wheels do track
the bumps in the road more(ie. hit a pot hole on the left the wheel wants to go left)
This is not a problem for me, you just hold on to the wheel. i do not mind the increaced imput, i must also point out that i went form 15"-16" wheels at the same time.
I have herd of clearence probs on lowerd subes with 225's but very few with 215's
you will also have slightly poorer fuel mileage with wider rubbers.
so its up to you what you want.
just my .02$..