Sith Droid Mark I: 2d6 - 4hp
Sith Droid Mark II: 2 upgrade slots
Sith Droid Mark III: 2 upgrade slots
Sith Droid Mark IV: 2 upgrade slots
Sith Droid Mark V: 2 upgrade slots
Sith Droid Mark VI: 2 upgrade slots
Sith Droid Mark VII: 2 upgrade slots
Sith Droid Mark VIII: 2 upgrade slots
Sith Droid Mark IX: 2 upgrade slots

(Dice increase past 10d will instead increase the dice size by 1 pr. d6; e.g. 12d6 will become 10d8).

Free upgrade: masculine or feminine programming.
Combat upgrade increases the droids dice pool by 1d6.
Armor Upgrade increases the droids hp pool by 1.

Upgrading a droid:
Depending on the kind of upgrade the droid needs various steps needs to be taken, for instance an armour upgrade might need collection or manufacturing of a special material and combat upgrades might need several combat experiences to be stored in the droid's memory modules.

Common droid series:

Sentinel Droid
The most commonly used droid in military operations, they are usually equipped with blaster rifles and sometimes carries personal energy shields. Outward appearance a sentinel droid looks as an armoured humanoid.
Upgrades: 1 combat and 1 armor with each rank

HK-series Droid
Originally of manufactured by Czerka corporation, the Hunter Killer droid series is an assassin droid with extensive programming on how to complete it's given task most efficiently. They appear as a (sinister looking) protocol droid, usually with a very distinct shaped head.
Upgrades: 1 armor every odd rank, rest in combat

Protocol Droid
Not build for combat, protocol droids usually take on a role of an assistant in some area it has been pre-programmed, usually etiquette and translation. The appearance of a protocol droid can vary much from species to species, but the most common appearance is a humanoid protocol droid.
Upgrades: 2 armor with each rank.