The DR won't let you import a car more than 5 years old regardless of how good condition it's in because they want only nice, newer cars, yet the roads are full of wrecks, junk heaps, and jalopies.
They won't let you import vehicles older than that, but once the vehicle enters the country and the aduana/DGII has been paid what it's been paid, the story ends... No inspections, worst case scenario no competent mechanics, so it's with everything govt related, all that matters is that shiny things are imported but the stuff that's in here, can be treated like s**t... I recall having heard about inspections being started a few years ago, but then I suppose absolutely nothing came out from that?
This is one reason why I do not prefer to travel by taxi, rental car nor a guagua... I don't know in what condition they are in.... If the vehicle is mine, I know the condition and can influence it... I can even do all the work myself and get parts from abroad I like to... Then the only thin I have to buy in the DR is gasoline and possibly engine oil...