I don't know what offset the ph. 1 OZ's have, but I've got 205/50's on 15" OZ F1's which have an offset of 37. One of the effects is, that I've got some slight rubbing on the outside of the rear wheel arches. It's not much and could be cured, but I haven't gotten round to it, yet.
Apart from that, 205's should give a little more grip as opposed to 195's, but that depends on the actual tyre, of course.
Oh, and than there's of course the other effect, that 205's look cooler. Especially if they're Toyo R888's which are rather wide even for 205's.
