I would say yes and no. After much discussion with a few of my dedicated friends, we figured that there should be an "alien tech engineer" who can modify Guardian tech gear/weapons. However, we also believe that there should be a limit. They should only be capable of being engineered to G3 maximum. Of course, this would require Guardian materials... as much as I hate adding to the grind, there's no further use for these materials after you unlock all the modules and weapons. As a caveat, they should not have access to experimental effects considering they are already experimental in nature.
While it isn't "necessary", it would definitely make the Anti-Xeno side of things more interesting. The modifications that would be accessible should be unique to Guardian equipment. For example, the Guardian Hybrid Power Distributor should have access to a "heat based capacitor" modification, making your 3 capacitors recharge faster the higher your heat. Considering how Gauss Cannons barbeque your ship, you could use a heatsink as they max out if you consumed capacitors for boosting, recharging shields and firing weapons.
Just an idea. Probably unnecessary.
While it isn't "necessary", it would definitely make the Anti-Xeno side of things more interesting. The modifications that would be accessible should be unique to Guardian equipment. For example, the Guardian Hybrid Power Distributor should have access to a "heat based capacitor" modification, making your 3 capacitors recharge faster the higher your heat. Considering how Gauss Cannons barbeque your ship, you could use a heatsink as they max out if you consumed capacitors for boosting, recharging shields and firing weapons.
Just an idea. Probably unnecessary.