I still don't understand if you textured in truespace or max, and if the problem just happened when you convert.
If it is a conversion problem, then reconvert the ship with other tools.
If not, try to use lithunwrap.
btw...
the polygon reduction tool of TS suck for low poly models, but probably with more complex models it works better...
The small details (guns.. etc) are not very visible, so I can't speak of them, but you should be able at least to redo the main hull lines with 3-4k triangles having almost the same quaility level.
It is true that the fso engine can handle high polycounts now, and if you are talking of 17k triangles there should be no problems, but the fact that the engine can handle meshes with very high pcounts doesn't mean that you have to go for it even when it isn't needed.
I THINK the actual limit is around 25k triangles, you can untriangulize the mesh, reducing file size, but the triangle count must be below limits