I just got a Wildhare 300 Extra with a DA-50R 50cc engine with a Pitts style muffler. Awesome combination. I like the DA engine. Started up right out of the box and is running well. It is made in the USA and Desert Aircraft provides good support. You can email them with questions and they are quick to respond. There are ten guys in my local club who have DA engines, 50cc and 100cc, and they all speak very highly about them. The DA-50 is a pricey ($595) engine but I believe you get what you pay for. Also, your Extreme plane is a real nice plane and it too is pricey. When your are done you will easily spend $2,500+ and at that price tag, you want a really dependable engine. That is why I went with the DA.