I have landed my spitfire a couple of times pretty hard. I found one of the weak points int the spitfire is the front wingbox. The foam just doesn't hold up. So I made a reinforced front wingbox for he spitfire and my BF-109. Let me know what you guys think.
I will get plans up shortly. I wrote and article for Flitetest that should be up soon. I will get the plans in this thread too. Hopefully tonight.
Also, I have kits for sale at http://attituderc.com/store
BTW, and you tried putting a foam layer over it yet to clean up the bottom? (I perfer a few stratigic pieces of re-enforcement, but it's nice to keep the materials looking uniform)