Having spent some time underneath my 1988 Superior lately, it does not seem like anything was changed, with exception of lengthening the drive shaft, brake/fuel lines, and wiring.
I recently replaced the front brake pads, and the parts are just standard for the Cadillac Brougham sedan used for the conversion.
As a side note, I did notice that there are grease fittings on the drive shaft that seem to be non-Cadillac in nature, likely added during the conversion. It seems that the drive shaft on many of these vehicles may be missing out on grease because you can't really see the fittings unless you are searching for them. I know mine had not been greased for a long time.