RE: 3W / BME / ZDZ / DA-->50
Having first hand experience with 3 of the engines, DA, ZDZ50NG and BME 50. I would not by another ZDZ50NG. If I chose a DA50 I would only buy a NEW one from DA so I would be getting the latest mods. The BME is more powerful than the ZDZ50 with stock mufflers. The DA is probably a little more powerful than the BME but as I recall it costs about 100.00 more with muffler.