Import Trouble

I can't see why you can't just download the model, import it and change the paths. They are organized in folders if you haven't noticed, and the models creator will usually tell you if there's an unneeded skin in the archive. It's not that hard.

If anything else fails:
Open the model file (the .MDX, first you convert it to .MDL using War3FileConverter).
Then look for the part in the top that says

Textures 2 {
	Bitmap {
		Image "abilities\Spells\Undead\Impale\ImpaleArm.blp",
	}
	Bitmap {
		Image "Textures\BloodWhiteSmall.blp",
	}

There you see what the proper paths are. Here it is "abilities\Spells\Undead\Impale\ImpaleArm.blp" and "Textures\BloodWhiteSmall.blp".

You don't need to convert it. Open the .mdx in notepad, it looks like justy a big jumble, but the paths are clearly stated near the top.