Personally I would be a little worried about buying one off of Ebay or market place. Never know for sure and that the brains of the Slingshot. If you get a bad one from a dealer of a known vendor (DDM) you will have a recourse for a replacement. The 2015 & 2016 had a headlight problem that caused some recalls. don't think there was a problem with the 2017...check fuses.
I have contacted Dave. I’m hoping he can give me some guidance. Thanks!