Hi
The top listing in that Ebay link was for these:
SET OF 4 Wheels. Front 7.5J ET35 & Rear 9.0J ET16
replacement Fuchs style wheels.
BLACK CENTRE with POLISHED outer rim
Its the ET35 and ET16 numbers you need to pay attention to as they indicate offset
Have a look on your car and if it has original Porsche wheels then the size including ET number should be in the casting by the valve, you can then see if they are a direct fit or maybe you might need spacers the width of which you can calculate using one of the many online offset calculators...
http://www.1010tires.com/Tools/Wheel-Offset-Calculator I don't know your original 951 figures so either look at the rims on your car or search this forum, someone is bound to have mentioned fitment before
Cheers