Weapon enhancement such as weapon upgrade and optimizer ROM is more scarce compared with weapon enhancement from device in general shop such as Starton. I think they should be sold by arms dealer, much like armor dealer that sell armor enhancement barrel.

This also should be done on shield enhancements too. Armor dealer should sell some shield crystal and ROM.

the_shrike 19 days ago:

Personally I'd give them to tinkers, but a reliable (if uncommon) source of them would be reasonable.