If you have a club near you, talk to the modellers. You will find that they are an approachable bunch. Find one who runs a boat you like and talk to him about it.
You will probably find, as indicated above, that very few use a completely unmodified RTS boat, since commercial pressures always bring some limitations. Modellers often change the battery, to get better duration, then the radio to obtain better control, and finally the motor to get more speed…