It is quite fast for the average RC car except for now there are RC cars are available to go 100 MPH
Watch it
65MPH
100 mph
You can rent fast rc boats at various hobby shops that cater to these vehicles. You can also visit large city parks such as NY Central Park. They have places to rent rc boats.
I have been looking at rc boats and i saw one that go's up to 20 miles an hour but i didnt know if that was a fast electric boat.
about 50
Ebay
366mph (516kph)
The fastest rc boats in my opinion are the ones made by Fine Designs. These are extremely fast. I've witnessed a custom Fine Design go over 140mph. Is that fast enough for you?
There are thousands of rc subaru rally cars so it is nearly impossible to know
Aqua Craft, Proboat, and EP Racing are some brands that sell fast RC boats. Here is a website that shows competing prices. http://www.offshoreelectrics.com/.