Falcon,
My car has 7" and 8" x 16 wheels. It originally had 15" fuchs from the factory. It looks like your car may have the 15" wheels as well. My car is lowered to close to euro height. It was lowered by a mech. when I had larger torsion bars installed so I don't know all that's involved in lowering.
Also, if you haven't already heard about Cardex. You can get the build info on your car from Porsche Cars of North America. I haven't received mine yet but I think it gives all the details on options, color codes, etc...
Don
87 coupe
http://www.pelicanparts.com/gallery/don911/