Yes my biggest challenges are the clutch issues but that is because I decided to use another trans.

Dan H. (Houlster) finished his and also used a different trans. He designed his fuel delivery and spark timing through a custom controller you build yourself called megasquirt. I elected to try the same as it is completely custom to your desire, patience and particular setup. www.Megasquirt.info

You of course could resuse the stock ECM, wiring harness and ZU trans. Going this route, at minimum you are looking at:

-custom motor mounts
-modification to your clutch mechanism (probably just lengthening or -shortening the slave cylinder shaft particular to the buick pressure plate.)
-modifying the charging circuit

then it's just a matter of making the connections between zu and buick:
-power steering
-starting circuit
-HVAC

Probaby left some things out but that is the bulk of it.