If you show up at the airport with a 55'' tv with the intention to transport it as checked baggage, forget it. It is oversized, fragile and high value, they won't touch it. The agents will direct you to the airline air cargo office.
The amount of money you would pay for freight, insurance, and customs would be obscene.
Rethink your options. Maybe someone can provide a price for a unit bought within the country and you can crunch some numbers to find out if it is worthwhile to import.
Also, should you import, the aduana nazies will value it on whatever they desire with an additional fee because it is electronic (energy consumer) and if you are not of Dominican heritage there is a surcharge.
Regards,
PJT