If tgens were upgradable you could do more with modules too like certain powerful mods might require a certain level tgen. there could be different model tgens, like one designed w 2 lamps and 2 heavy duty mods and then other iterations. gives more incentive to hold onto territory and towns etc. it would be expensive to upgrade and change your tgen model for the possibly better mods or players could start choosing their tgen model/mods based on the terrain of the territory and stuff.
but you'd have to level up your town and hold territory for X amount of time to unlock and be able to pay for said upgrades/models.
but you'd have to level up your town and hold territory for X amount of time to unlock and be able to pay for said upgrades/models.