i had 10.5' all around on the 1st generation and sat right under the plastic arch, but not sticking out, i think the 2nd generation should have more room
I believe someone on this forum (Sydney?) is running 20 x 10, 40 mm offset on his 2009 FX. It looks nice and flush. So much so that i'm almost considering going to that wheel size myself, and I have a '10 FX50 with the 21" Enkei's!
I have 20-10's on my 09 FX35 with a 45 offset and they are pretty flush even with HANKOOK 295-45/20's on them. Check out my pictures on my profile. Hope this helps you out.