195/70/14's are what i have on my 14's.
do your wheels feel a little heavy? if so thats a very good sign they might be fakes. to make sure check the back for a porsch e parts number
if you look on the back of the wheel... (you see the paddles on the front when they are mounted to the car, look on the back of the paddles, the part you dont see when they are mounted on the car) look on the back of one of the paddles on the back side of the wheel..
should see somthing like this.. either a 901# or 911#...
that is the most important thing to look for. that number. that means it is a genuine porsche part. only real fuchs have those numbers. they may be a bit warn down depending on how your wheels are. also they may be gunked up with brake dust, gunk, etc.. so you may need to clean em some. (see how grimey it is in the pic above)
the fox is a bit harder to spot in my experience. be sure to find a porsche parts number though.