Maybe they were supposed to dispose of a vehicle (or a number of vehicles), decided to sell them and make some money instead?
Yeah, I dunno. Doesn't sound big enough to me. Disposing of, to my mind, would likely include selling, after switching VINS, a paint job, whatever.
But the same folks who buy wholesale for distribution tend to have their own disciplinary problems at the street level. Folks try to move in on established territory, or don't manage the cash to make good when merchandise is fronted to them. In the city, it's not at all uncommon for a killing to appear in the news and then disappear--frequently because nobody but family cares too much. And then months or years later there will be some major take-down that leads to resolution of some murder from two years back.
I think (JMO) that the cars are pretty much incidental to a larger, and illegal, business. Because they are tinkering with cars anyway, and because they have this other connection anyway, they are poised to offer a convenient service to some folks who are jammed up up in the city.
I continue to believe that whatever spurred this execution was either a move that cut out a major distributor (by switching to someone else or by attempting to go it alone) or else the suspicion (whether true or not) that the Rhodens were working with LE. Either one of those would put an organization in major jeopardy.