A stock 48cc 2-stroke motor has 1.95 HP or 1454 Watts.
200W = 0.27HP
What exactly is this $89 '200W Limiter' and how does it work on a 2-stroke gas motor?
1/3rd HP with all the human power you can muster (1/10 HP for an athlete) added in is a completely laughable power restriction, heck I have cordless drills with more power than that.
Heck some gas powered RC planes have more than that and they can barley make 30MPH.
You have to decide if want legal or fast because with a 200W total power assist you'll need to defeat the laws of nature with the bike itself or start doping like Lance Armstrong.
Drop a 200W electric assist on that 'bullet' bicycle and you could run with cars on the highway, just add another 0 to the end of your $400 budget ;-}