I spent a lot of time cutting a hole, building a hatch, shelf, etc. for the battery, and it flew like Sh**, so after one flight I moved the battery back up under the wing. My CG was 6" maybe 6 1/8", now I'm about 5" maybe a touch more, it's much more stable, and with my insane control throws, it still does all the maneuvers. I think there is less coupling with the foreward CG too, although it's still pretty bad.