i have to agree with Rokiyo, my fps data ( http://i60.tinypic.com/ndo3ft.jpg ) also shows a approx. 4ms increase in time per frame... that is worth looking into i would guess

confirmed fix

you still need those mass enhancers on the base of the turret (where the barrel is docked to)

The ball turrets (they look awesome btw) are lighter, every dock has 50 mass "free", so only the bigger turrets need mass enhancers to support their barrels.
also: You only get that 1% speed message if you enter the barrel normal from astronaut mode (not switch up from the base or mothership).

can confirm the issue that starmade minimizes when tabbed out, haven't had a problem with it (it always reopened so far)

There are no mass enhancers on the base of the turrets. At entering the barrel i get the message that it only operates on 1% of speed.

I had no success reproducing any of those issues, either i do not correctly understand the initial bug report or those bugs got fixed right away.

confirmed

Confirmed in parts:

Well, i tried to reproduce the problem. Couldn't get reliable data from the CPU (poor signal to noise ratio :( and i would need a better logger if i would go for some statistics...)
But: FPS alone gets hit heavier than i expected:
http://i60.tinypic.com/ndo3ft.jpg
(130 sek, 10 sek normal, 10 sek advanced, inside a 50k mass ship)

Could not reproduce the claim that pirates will move out to maximum weapon range, in my tests it always seems to be about 50% of max range.
Still, pirates will move out to a range where they can not fire their other weapons (eg. a pirate ship with beams and cannons/beams will move out to about 50% of the cannon/beam weapon range and thus can not hit their target with the beam).
Pirates would even disengage by themselves as they move out of their engagement range. Does not seem to be dependent of AI difficulty setting.

confirmed

confirmed.