Here ya go.
I apologize for the weird angles on the models, I have my tablet hooked up, and it doesn't have a scroll wheel.
Model, opened in .blend format with no problems:
Model, exported as .x, then imported back in as .x:
As you can see, the normals are inverted, it's at a strange angle, and, though you can't see it, it's much smaller than the original model (maybe like 50% smaller). I exported using the default settings, which never gave me trouble before. I managed to get the normals to export correctly by changing one of the settings, but the weird angle refuses to go away.
And to prove that it's not just Blender's .x importer going crazy, here's the model in FPSC:
It appears to have lost its strange angle, but its normals are still inverted, and it lags the editor immensely, compared to any other model I have in my library. When I run a test game, I only get 45 FPS when the FPS cap is removed, rather than the normal 3-digit number I usually get.
EDIT: I tested it again, and got 40-45 FPS with the model, and 75-80 without.
Thanks.