Can I install the 930s steering wheel w/ hub adapter?
 

Pelican has the wheel and adapter but does not have the hub spacer. My stock wheel, 85 carrera targa, has plenty of space between the wheel and the dash.

It's my understanding that the spacer is optional. At least that's what I get from reading this:

http://www.pelicanparts.com/techarticles/911_930S_wheel/911_930S_wheel.htm

R Man,
The dirty little secret of after market wheels is that many of them are too 'flat', leaving too little clearance between the rim of the wheel and the dash. The link that nostatic posted is a great example. Mine [a beautiful Moto Lita wheel] was the same. You will want around the same clearance as you get with the stock wheel, especially if you are autoxing or DEing.