I've been thinking about throwing my group into a rather military campaign, but I'm not sure if their characters are strong enough for it, so, I had the idea to give them a Gank buddy to fight with them, just in case. The problem, however, is that I'm not sure on how to make this Gank balanced, and not some killsteal-y giant in the early game, but also not a squishy load in the late game. I think one of my players was going to play a Gank for that campaign as well, so I've been considering a Gank Comm Implant. Any ideas?

Gank are either balanced by or utterly neutered by the rules you choose to use regarding ion weapons and cybernetics. Use the RAW and they are total crap. I suggest instead just having characters with cybernetics take strain damage from ion weapons (just like droids) and also having the option to damage cybernetics (as if they were any other piece of gear) by spending 3 Advantage or 1 Triumph.

Just keep the Ganks stats under control and he'll be fine.

Something like:

Gank "Observer" - Rival

B3, A3, I2, C2, W2, P1

WT12, Soak 5

Athletics 1, Coercion 1, Coordination 1, Ranged Light 1, Melee 1, Ranged Heavy 2 Vigilance 1

Cybernetics: Cybernetic Arms, Cybernetic Legs, subdermal armor, Respirator, Comm, Cyberweapon (Light Blaster Pistol)

Gear: Heavy Clothing, Combat knife, Blaster carbine or rifle, 3 Stimpacks, other utility items as appropriate.

Add salt to taste.

If you want to make him Nemesis level, just add 12 Strain.

Note that his skills are almost all combat focused and not hugely ranked, so the players will still do the majority of the rolling outside of combat and in combat he won't outshine the players for more then a couple of XP reward steps. Also check the cybernetics, they all provide fairly passive bonuses, so as the GM you won't have to always be remembering to apply this bonus or that special talent. Nemesis is an option, but it won't add that much and will really just be one more thing to track, keeping him Rival will streamline his operation and keep him one step below the players abilities so they won't feel like the GM is muscling in on their Hero status, but his above average soak and base weapon will keep him in the fight and allow him to hit hard, easily offsetting any player shortcomings at least for a little while.

As Happy points out, Ion weapons will cause him a lot of trouble. Fortunately, after the Clone Wars end, ion weapons go out of style in favor of more universally useful conventional sidearms. So your average dirtbag won't carry an ion weapon unless they know well in advance that they are going up against a cyborg or droid. Translation: Don't bother handing out ion guns to your adversaries on an average day, but once the Gank starts to reach the end of his usefulness, narrative, or the players start using him as a crutch, ion his fuzzy butt and kick him into a pit all Sparta style.