The Midwest Mustang flew OK with the Enya .15. It was not overpowered, but I think that the plane came out heavy because of the wing covering I used. Also, I was 14 at the time, and not great at trimming a plane. If interested I could weigh it to see where it's at (I still have everything hanging downstairs!), which is something I never have done.
I later used the same engine on a much lighter (and larger) Aldrich Peacemaker, and it flew great. So, today I think I would still use the Enya, but get better results.