>
>where can i get the factory model, and how much do they run?
>

You mean from someone else than VW?                                          
 There is a list of parts suppliers which you can access by gopher:

gopher halfdan.med.umn.edu
/Misc./Vanagon/Files/A-few-parts-suppliers
   
A few days ago someone mentioned that the one from J.C. Whitney (?) is not
as efficient as the original model.