I would suggest cleaning the car up and keeping it as a shelf queen. Since the HPI Proceed was discontinued a little more than a decade ago and parts are very scarce, running it regularly would be dicey if you break a part that you can't replace. Plus, with the newer cars with their latest tech designs, you would not get much for the car trying to sell it outright (unless a collector is seeking one). You can get some monies out of some of the other stuff (tire truer, Hudy setup stuff, starter box) if you are looking to get some monies out of the stuff.
It's not what you know; it's what you can prove.
The only thing that is for sure is that nothing is for sure!!!
The needs of the many outweigh the needs of the few, or the one.
There are 2 things in life that are infinite: the universe and stupidity.