I have them. I have Tested them. And..I can tell you. It will make your bike run much faster while keeping the RPM down and allowing the engine to last longer and run cooler. You will love the 36T. It may be too fast for some riders. Also.. You will give up some climb ability. But..It still climbs good and makes your bike go much Faster !! For sure !!! Thanks..Enjoy the ride.
I have used one on my 04 Stingray. With the 20 X 4.25 rear tire, expansion chamber, 55 cc Grube, with a Kings 80cc. jet. I briefly hit 38 mph. This is at the edge for this style of bike. For those wishing to go faster a 26" or larger rear wheel diameter will make this much easier to achieve with less stress on the engine.
As for climbing hills easier with a smaller diameter rear sprocket, well... not.
Starting difficulty is increased due to slower engine rotation and increased pedaling before engageing the engine is the trade-off for the several mph in top end you will gain using this sprocket. Its something I could live with.