Thank you folks for responding. Yes, I should have detailed some regarding requirements.

The wheel size on the Brompton is 16". And as far as speed. Well, I'm not all that concerned. Most of the time I'm pedaling around the 10MPH mark. The Brompton isn't built for speed. It's a nice recreational folding bike designed for commuting. If I can get a max speed of, say, 20MPH that would be enough, which would allow enough motor power on a slight incline. I would like a kit that would allow me to ride along without pedal assist, and with pedal assist if I choose.

Thanks again for your help guys.

Wayne