I fitted 5mm spacers all round but didn't like it at the front. The turn in is pin sharp and I think it felt a bit like fitting too wide a wheel. I am already on 195's at the front so they felt a bit overkill.
At the rear it just looks better and fills the arches out! Vanity!
I feel that there is enough stud length for me not to worry about it. Any more and I would have to fit longer studs and that's a real pain.