[JayG]

It also depends on how the studs are measured

Is it the full length, or just the amount extending past the rotor surface

These are what have
http://www.ebay.com/itm/20-Wheel-Stud-Conversion-14x1-5-TO-14x1-5-Studs-Adapter-Kit-63mm-2-50/261504562085?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%2 6asc%3D20131003132420%26meid%3D703bd76fddd1438b88a eecd42b84c758%26pid%3D100005%26rk%3D5%26rkt%3D6%26 mehot%3Dag%26sd%3D310852646707;


20 Pc Wheel Lug Nuts Ball Seat Porsche Open End 14x1.5 New

You want open ended lug nuts, so you can see that they are engaged with enough thread
That is also generally a requirement if you are tracking your car