Looks like you did a good job on it. Gmax is a bit of fun but buggy sometimes I've found, so that's no small accomplishment. The plus side is it's relatively easy to use and learn from and will help prep you for working with newer versions of Max.
Unfortunately Max is entirely corporate now and is endeavouring to find new ways of costing people money by cutting features from the base program and making them rather expensive addons that are-truly-more functional than they were originally from what I've seen.
Better maybe, but that's a heck of an expense from what I've seen, especially when they drop support for 'old' versions as soon as they release the new ones, which is every year at about this time.
I can't afford Max anyway so it's a moot point, but I wish the buggers would drop a new gmax on us without so many restrictions.
I'd happily pay 200 bucks for a slightly reduced feature set and open source friendly, (for add-ons and scripts), version of 3ds Max 8 or 9. I think that was the last time they had a full featured package that wasn't missing animations, IK solvers, texturing, and all the rest that they've all but removed now. 8 would be fine.
I trial tested 11 awhile back-about a year ago-and found it to be limited, cumbersome, and buggy. Didn't like it much.
Slightly off-topic there but you were saying you were learning how to use gmax.

Not that that'll teach you anything.
Here's the trick to texture mapping.
-use hide to view obstructed areas by removing the stuff in front with poly select. Basically just box select whatever is obstructing your area to work on and hide it.
- Use long more or less straight edges to determine the borders for your texture placement. Essentially if you are fortunate enough-or have designed with intent-to have a division between sides of a model like the center line dividing one half from the other on 0 x, y, or z for example, you can texture on both sides of that line individually and have your texture maps butt up against each other with matching but mirrored textures.
Not sure if that's explained clearly enough, but it'll have to do.
- Texture elements individually by selecting them and hiding everything else.
- Use tga images of the textures you want, (the diffs or specs depending on type of texture), unpacked to an X3 directory in the appropriate area. Documents\X3 Terran Conflict\dds for example, with dbox pointed at it), so you can see the images on the model.
You'll have to open the materials editor and individually point the program at the images. This is why I recommend just Diff or Spec because it can be very time consuming redirecting all and gmax doesn't really see the depth of textures anyway in my experience.
- To input Texture parameters you can delete all textures on the model through the editor, export it to bod format, open with wordpad and copy paste the textures you want. Make sure to number the texture id accordingly and in order and keep the original texture parameters in a wordpad to copy and paste back in later.
The exported textures are not the same as the original. gmax doesn't keep all the parameters. Use fewer textures rather than more. Trim, antenna, plating of 2 different types, exhaust, etc..
Re-import with the added textures, open the material editor and click on the little blue and white icon for each texture referenced to make it visible on the model.
Save as new file.
Select your area by poly and apply a texture. Try a flat surface first and adjust the texture size and coordinates for placement. Practice a bit and figure out the basics then open your save and go from there.