I know the code is horrendous, etc, etc, BUT The idea is this, add a separate column/icon/category (whatever you call it) for weapons/armor/engine that the commander has researched. Essentially separating the stock equipment from the upgraded items available to the team. This would allow players (specially those who just joined) to quickly see what their team has researched and then equip the best possible tank for the field. Pain in the ass to do?
You're essentially saying add an entire column just to filter out Std engine/armour/weapons. I mean, given the future plans to allow restriction of specific things by commander, I don't see the need. I get the reason why but I just don't think it's worth going into the vehicle GUI code and reducing coders to tears for what it will add.