This page on the Scrappydogscooters site lists the Strada 200HP as being part of the GY6 engine family.
http://www.scrappydogscooters.com/12...rformance.html
If I read that correctly, you should be able to substitute the 200HP engine in your 150.
All engine swaps involve some basic mods to hoses and wiring, but engine mounts should be the same.