There might be some value to the vintage racing community if they truly exist. The XX4 was added to the list of legal chassis at the Vonats in 2014. That said, you're going to be hard pressed to get big $ out of a kit that has been superseded by the 22-4. There's some value for the vintage folks, but for something that is going to be raced once a year you're really competing against built rollers and parts cars for sale on eBay and RCTech. NiB is nice, but don't expect much of a premium.