Just finished installing them on my gun and two batteries.
So easy, even a caveman can do it! (Thanks GEICO Insurance Co!
)
Observed a good BB RPM inscrease with the same battery and setup.
Really impressed, as for size, well I dont really care, I've got a full stock M16, and a M4 with front handguard battery placement, still no issue.
EDIT: MaciekA, how are they holding up for durability?