JS31
Strictly personal, the 31 is underpowered. Hot and Hi performance forced BAE to spit out 32EP (stands for enhaced perf.) Massive ldg gear suitable to carry JS41. Not quite sure if it is certified for gravel/grass but JS41 operates from those in SA, I think.Basic info can be found on BAE Systems web page and contact with Woodford is good advice. Also you may find some info through BAE Sysytem Asset Mngmnt which can be contacted via main web page of BAE. If I can help PM as well, I used to fly it some time ago. I used to train in Woodford, a lot of good people over there.