@consigliori sir @jstblaze10 should firstly reach out to his friend who sourced the car for him. it is far better to resolve the issue peacefully rather than being adherent!
i am quite sure that the previous owner knew that the car had fake documents & registration and the current owner must have gotten it a little cheaper than the market value.
if the problem is not resolved you have two choices! either you report the car to the authorities in which case the car will be confiscated and you will get nothing except khuwari, if the owner has some sources in Excise he should consider getting the car legalized which is not possible!
Else if you can bear atleast half of the cars worth, scrap the damn thing out and sell it as parts!