How are these handled by you/your GMs?

Mine seems to believe integrating would require a mechanics check, as if adding an attachment to an item.

I believe it's just how a Droid equips some items. It doesn't buy a suit of heavy armor, it buys a set of heavy armor plates to replace its standard ones with. Does a human roll to change its clothes?

Maybe I roll to alter the item so it can be integrated, but then shouldn't every non-human roll to do the same? With likely hundreds of thousands of manufacturers in the galaxy wouldn't you think you just purchase the version of an item suited to your race?

I wouldn't call for a roll. Rolls are only required when there's something at risk of loss. Something of importance. So even if it takes a wrench and a driver to take off old metal and put on new ones, it can be done during down time without any risk. That'd be my call.

I would agree with you, there are probably thousands of various blaster Rifles that all fit within the description of Blaster Rifle, some of those are designed as weapons mounts for R2 units and can be fitted just as easily as an attachment.

IMHO anything can be fitted to a Droid with the only limit being Encumbrance. The actual question that a Player and GM need to answer together is "can the item be seen or is it concealed?"

A Blaster Rifle on an R2 is not going to be hidden, a Pistol could be. The DR-45 Dragoon is a great fit for a Droid, it's hidden inside but for a maneuver the long barrel extends out and becomes obvious, but provides greater range. And just like hiding anything on your body there are people who can spot those modifications.

So the only roll I would ever ask for is to install an item where it's to be concealed, difficulty is the Encumbrance of the item, number of success sets the future difficulty for others to spot the hidden item.

So the only roll I would ever ask for is to install an item where it's to be concealed, difficulty is the Encumbrance of the item, number of success sets the future difficulty for others to spot the hidden item.

I think this is very reasonable. The only other factor that could warrant a roll would be time, or at least the only other one I can think of right now. A change of clothes on a humanoid still does not take as long as changing the plating on a big, bulky droid. Depending on the droid of course. In general I would just let players do that, but if time is an issue, maybe let them roll mechanics to see if it is fitted properly. That is such a rare occurence though; who would change armour if there is no time. So yeah, just let encumberance dictate what is possible and you should be fine.

What about Advantage spent to make a droid drop integrated items? I'd say no mech check to install them, this way dropping them doesn't raise a stink. Pdrsonally, I say.