Motive - This is why I believe the truck is NOT the motive for the crime. Maybe they had an order to chop up some parts for that type of truck, or whatever, but, the real motive was the thrill of the kill, IMO.
The



had the $ to buy or simply just steal the truck outright in the middle of the night.
Three - 3 - potential other victims were not preyed upon in the end.
Tim was chosen, because he was slight enough for them to murder. In my opinion, they were making some wacked out snuff video to distribute, because they enjoyed the thrill of the kill.
Evil, psychopaths.