Ive been there, done that. Got a 'steal' on a Quad machine with a ton of feeders last April. Still don't have it fully functioning. It takes tons of time, thought, and cash to make it work. My ex-partner had an unsupported P&P with feeders that he gave away to the scrap heap since the effort to make it a viable solution was more than buying a fully functioning used machine that is still supported.
These machines look awesome in your garage, but unless you have piles of time and money, they are worthless. Anyone that would by it, needs to make money and likely does not want a project of that magnitude. Even if the parts are available, they will be very hard to get and/or very expensive. One little thing that is scratched, bent, or burned up can stop these machines cold. Most of the parts are very specialized and difficult to DIY.
He keeps saying "$20!" but he already said he spent $700 in transportation alone. Good luck! At least the machine I got is still fully supported top to bottom - and it's still a major challenge.