If you are into sail boats you can buy almost everything that Victor Model Products has in their inventory ready built. As to power, if you are looking at tugs, check on Tower Hobbies and the other on-line suppliers. Robbe makes beautiful tugs as does Billing Boats. The usually have the hardest part, the hull, preformed out of plastic. You would still have to complete the deck and house as well as installing the power and drive line. A good deal of work left to be done when you buy the kit. You could truly say that you built the boat.