80cm length seems to be about the average length for scale model boats. With a mild performance type boat you should have no problem (unless you are in a remote area) in finding items without breaking the bank.
It probably would be helpful if there was an easily findable section on Model-Boats that new members could access such recommendations. This is probably the most common question and undeniably there will be many, many opinions.
Also, the Hobbywing 1060 brushed is a top performer for the price (I have at least 10). Don't worry about the fancy motors. An inexpensive 3xx series will work fine.