I don't want to just paste the upgradability to other mods. The tiered approach fits for Bob's mods, since they contain other multi-MK-turrets. IR2 not so much, it has basically just one of each turret type, with the option to upgrade the stats through research.
This needs a bit more insight on my end to make it fit just right in the end, I never played IR2. If you already have a possible progression in mind that fits the style of IR2, please share.