going from 205s to 215s would not add protection against curbs and pot holes....going with a higher profile tire would do that..like 50 profile instead of 40....
i'm assuming you are getting them in the +40 offset..that was the only offset available for my 17 in. RH M7000s...i originally planned to go with 205/40s to help reduce the chance of rubbing..but tirerack recommended i get 215/40s..so i did just that...i rubbed like a b*tch at first (keep in mind i'm lowered..check out my sig pic), but after dremeling the two little nubs in the rear wheel wells, problem solved...i also stiffened up my rear suspension (i have adjustable shocks). i am now very glad that i got 215s b/c the handling is amazing...
if you're at stock height, don't worry about rubbing....if you're lowered...just remember to address the issues i mentioned above (shaving the nubs/stiffening of rear suspension if possible). also, you can't have your car slammed to the ground..unless you want to roll the fenders. good luck w/ the new wheels ...if you have any questions let me know...i researched this topic for a while just recently b4 buying my new tires/wheels..