If the armor is generating a lung, why would the human DNA have to be tinkered with? The lung is a part of the armor. It is performing a function that serves the host, but it is generated by the armor. Like an organ donor, but superior and without rejection issues.
Why does the DNA have to be tinkered with in order to regress the origional lungs? When I squish a grape, does its DNA change? It's theoretically possible to manipulate organs without genetically engineering them.
So the DNA is changed to store more energy? Would that be the mitochondrial DNA, or the nucleaic? Does the DNA change when a virus enters the cell (aside from what the virus is trying to do-destroy the cell for reproduction). Lots of things can enter the cell without the DNA factoring into it. Such as the element that you are trying to insert into the cell to manipulate the DNA in the first place
sigh.
The unit-g kind of looked like a slime monster when it first bonded to Sho, Lisker, and Valcuria. That suggests that yes, it can bond to any form. But at the same time the armor seems to have limits. It uses human muscle tissue for some reason, as if the Creators developed life on Earth with the most advanced muscle proteins already. The frequency swords run on a basic principle of vibration, they dont get more powerfull for different species, you either have them or you don't. But at the same time, there is a charge up for the megasmasher, yada yada.
There are fixed stats on certain weapons, and a few variables. The power level of the boost armor mergance will depend on what the armor has to work with technologically. If a creature like Thancrus already has frequency swords, the armor can't really improve him in that area, but it might do a better job at expelling heat than his radiation fin, and might decide to add flight abilities to him. (actually, the Guyver swords are superior, but I'm trying to make a point)