Great vid. One thing you may want to check is the tire pressure! It may just be the road, but it sounds like the tires may be a little low. If their low, you'll lose 5-10 MPH easily! I know on my Elite 150 it'll top out at 58 MPH with I have them at 20-25 PSI, but at 40 PSI with the zippies it'll hit 65+ MPH on GPS. It will also make a huge difference in throttle response, it'll be much better.
Just something you may want to check. 400 pounds is also a lot of weight for a 150 cc engine, they really don't put out that much power.