For instance...take Artificial Arms. If you equip them in your utility slot - speaking of which, how would you go about unequipping them? Just strap your arms back on and the job's a good'un? - then how are your stats affected? The stats are 2 Strength and -2 Stealth.
Pretend you have 3 Strength and 1 Stealth. You equip the arms. Does your strength remain at 3? Does it get set to 2? Or are they boosted up to 5? Likewise with stealth; does that get set to 0, or is it -1?
I recently had a cybernetic eye installed. You equip the item, then you go through a 24 hour timer for a procedure that requires a doctor, npc nurses and a medical faction. Afterwards you have to go through a bacta tank session as you are at 1 hp.
The cybernetic goes into a separate inventory slot that doesnt show on the equipment screen. Once you have it the cybernetic will apply a skill buff or debuff, so my 2 in diplomacy becomes 2-2 for a 0 in diplomacy. The buffs go away if you undertake another surgery to have the cybernetic removed.
This is also all on the handy cybernetics rules page.