The mesh convertor(and merger) is quite stable and useful now. IMO you definitely should try that! If you just want to use the scratches in vanilla such as changing one's weapon or helmet, etc. It would be a piece of cake! And also you can use milkshape to export the converted model in .3ds or .obj format which can be edited in MAX and import to milkshape again and finally into the game.
BTW, I guess there won't be a MAX importer/exporter for mesh file as the time being
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PS. I myself has no experience in 3dmax and even no experiences in 3d tech before GOM made his convertor. but look at this:
I made a new helmet
I think you can do much better with more experiece(another modding legion maybe?).