Warfull, I just checked your mod and I must congratulate you on setting the record.
I'm not going to work with your ISD in PCS2, as it's the most poly-heavy POF model I seen.
I didn't seens such large file size on a model since I was working on Maalik for BP, which was scrapped partly because of that.
Small number of textures may be it's saving grace in game, at least on good computers, but doing anything in PCS2 with it would be a nightmare. It managed to make PCS2 lag
untextured.
In general, ship models of this size should be about 5000kb in size.
If it has more than 10000kb you better make sure that it doesn't have too many textures, or else you will get the same recation as Steve'o's craft, cool but inefficent.
Maalik and X3 ships converted to POF in general have around 25000kb and a small number of textures, and it was called inefficent. as it's usage would have prevented anyone with weaker computer from playing WiH.
Now, we have your ISD.
It has 52000kb of disc size, around 200000 polies on LOD0 and 5 textures.
Maalik had 30000kb of disc size, roughtly 100000 polies on LOD0 and 4 textures. Both are LODed, but Maalik had 4 LODs while ISD have 3.
So, this ISD takes the title of most inefficent POF I ever seen.
Now, don't get me wrong if that sounded like a rant, it's an excellent model, but for Hollywood movie or a game for quantum computer (I'm not familiar with X3 modding, but it looks like it would be called unusually detailed even there).
Those models need optimizing before taking them into game, this:
http://www.hard-light.net/wiki/index.php/Modelling should help you create efficent models.
I'd recommend taking a look at the structures at the broadside greebling and the entire superstructure, I'm sure that a lot of polies there could've been replaced with a normal map and that they are the parts where most polies are used.
There's also one more thing to consider when making a model: the popularity of a ship.
I could have accepted such polycount on a one-of a kind Eclipse-class SSD (Emperor's flagship from EU) or a Death Star, but ISD in one of most common Imperial ships in SW universe, so it's likely that there will be two or three on the battlefield. And finally, don't forget that ISD is merely 1600m long, so most of it's details (especially on aformentioned broadsides and superstructure) are not going to be seen unless you sit close to it and watch carefully on a high-res monitor. Ergo, there's no point in making it so much detailed.
Take look at the work of BrandX, as his fighter models are both efficent, beautyfull and accurate to references. He once had an ISD, but it was most likely lost in HD crash.