So good! That reminds me I need to get my beamspring pictures together. Such a great looking board you've got. Is that model a fully metal case? My 5251 (which I'm typing on right now!) unfortunately has a plastic shell top piece.
As far as I can tell (since the paint is slightly peeled off), both the top and bottom cases are metal, but I'm not sure which alloy.
How does it feel? Did you suffer any damage to the beamsprings when you took the inner assembly apart and exposed the flyplates? I've heard some people have had them spontaneously break when opened which has made me wary of opening mine up for a thorough interior cleaning.
Admittedly I wasn't too blown away by it at first, since I'm used to the huge fall-off in pressure on the Model F (20g as opposed to 10 on beamspring), but it's grown on me in less than three minutes of use. I can't use it too regularly before my xwhatsit's controller arrives, however. I don't think I broke anything in the process; the controller needed some persuasion to come off, but other than that there was no force needed.
They definitely test your ergonomics with that steep case 
Makes you a better typist, and they're fun as hell to type on 
I think you're supposed to suspend your wrists when typing on a typewriter; I guess same story with beamsprings.
