if you have to have a diesel why not use a modifed Mercedes Diesel? they are cheaper and fairly easy to modify And a Heck of a lot lighter too. The VW can be made to generate a lot of power too. a Cummins 4bt,6bt are just wayy to heavy for you application. also you could look at a modifed 6.5 GM they are good engines if you get the right years and there are forums dedicated to them .The 6.5 also uses regular chev mounts and transmissions(modified governor)