I’m typically NOT a big fan of high performance used parts, no matter how tempting of a good a deal it is .
High perf parts are usually beat on, pushed hard & abused. Just my .02
I’m with OHFIVETJ if it’s not abused then it’s a great deal, but you might want to get someone that does superchargers for a living to find that out. That or give it a real good look over and take the risk.
All I would say is beware the $950 is just the cost of entry. It's going to cost allot more to get it up and running. Forced induction is a very deep rabbit hole.