Just a note. I have been flying foamies (early ARF's) from 20 years ago and again started this spring. Yes all the foam wings fold up on high g loops. A simple and cheap mod is the following:
Go to Staples or another office supply store and purchase a roll of fiberglas reinforced strapping tape. On the Firebird run at least 1 if not 2 strips of tape lenghwise evenly spaced alone the wing, the same can be done for the tail. Run the tape all the way across the wing from wingtip to wingtip. You will find this greatly reinforces the wing without adding weight. I have moved on to 1/4 scale now but the aerobird extreme I started on again is still flying, capable of vertical flight and extreme loops without folding the wing.
As to higher capacity batteries at lower cost. Check on the other auction place and you will find the same voltage batteries with as much as 2 or 3 times the capacity. My Aerobird extreme flew over 1/2 if I wanted it to. Just my 2 cents worth.
Enjoy!!