We have the option to reinforce shields or hull, equip Stealth devices, Engine upgrade even on veeeey slow ships ( Y wing, B wing etc... ), but not to gain the Barrel Roll Action.

Playing home made escenarios we give selected ships this option quite often ( x wing a lot, little x wing mod ), but I want to create a upgrade that gives you the Barrel Roll icon.

I am not sure about pts cost. Perhaps 3 pts, and only small ships

Suggestions?

I'm torn on this. You see x-wings kindda barrel rolling in the films and i'm a firm believer in the x-wing in particular needing a defensive boost (like a re-positional barrel roll would do) however, i have had it pointed out by friends that one of the main differences between the slower/tankier rebel ships and the faster/nimbler imperial ships is the barrel roll, and giving wholesale access to a barrel roll to the rebels will nullify this design difference-i think they have a point...

There's always going to be manoeuvres that you wish you ships had and which would be greatly beneficial, however, i believe one of the challenges of the game is to compensate for the limitations of your ships by piloting skills rather than have access to an upgrade that could ignore any such shortcomings. tbh i don't like seeing large base ships barrel rolling either - if a small ship can't barrel roll in the game natively (let's assume it's thematically because it would complete the manoeuvre too slowly, like an x-wing, vs one that can, such as a tie fighter) then a larger and therefore presumably less nimble ship barrel rolling just doesn't feel right to me, but i digress...

In short, whilst i wish a lot of ships that don't have it could have it while i'm flying them i think on balance it would not be a good thing. If such an upgrade did come out i wouldn't use it in casual/GNK play however i would in premier events where the self imposed limitation would be far too high a cost.

On points i'd cost it more like the engine upgrade (4pts) as it is a potentially more powerful upgrade than shield/hull and (unless paired with a handful of astro's/EPT'S) a re-usable enhancement unlike shield/hull...

How about "Expert Handling"?

Exactly what Bikeanimal said. Its important to have at least a small difference left. There are ways to get ships to barrel already Expert handling, BB-8 I personally feel that is enough.