> Both in terms of the cost of components and the labor needed to figure out each vehicle's specific conversion, this seems expensive, slow, and perhaps is a source of quality/safety concerns.

We are speaking about countries where that sort of labor costs between $0.5 to $3 per hour. The parts used aren't factory-new and the cost of labor is minuscule in comparison to the price of the vehicle.

There is no money for safety. You make do with what you have.