I don't know if this will really help you, but this is what we've done in the campaign I am playing a mechanic in.

My mechanic salvaged an astromech droid after a combat we had early in the campaign. I spent several sessions working on it in my character's free time. After "completion," the droid was able to assist me. It has no stats and the GM always describes what it does after I give the droid a command and usually it simply adds a [bOOST] to my checks in a sort of Right Tools for the Job role.

The droid is really only vulnerable if I send it to do something stupid or if I roll lots of threat or despair. In essence, it acts like a piece of equipment.

Well from what I could see from the many posts that are up from this thread I started here & in AoR, the NPC Droids are really up to a lot of interpretation and implementation on the GMs since there isnt a clear cut set of rules on how to manage them. I can understand that they are minion class NPCs and they have a stock set of stats in the book, but there isnt a clear cut rule set on how to use them...as just tools or having their own set of stats that isnt a PC per se but can actually do rolls on your behalf for astrogation or mechanics or computers or whatever you have them for to use. So I would like to see in AoR or some supplement that addresses these issues more concretely.

What's the deal with the naming conventions of the R-model astromech droids? R2 was clearly top-shelf in Episode 1, but during the clone wars Mace Wendu has an "R6." R2s traitorous replacement was that golden R3 model for a couple of episodes, which is feasible, but unless there's a naming thing going on when owners customize their droids (+1 to naming after each major update) I don't see a system behind different surnames for droids that are the same model. Narratively it makes sense to have R2 be the R2, since having several of them in one scene would confuse things, but if one refers to it as an R2 unit there could be an R2-A1 or R2-Z9 or any number of name mixes to ensure that we don't have to wonder why a droid 4 generations in advance is working next to its not-significantly-younger "sibling."

The R-series.

Great link. I was kinda wondering this myself. They kinda stretched it to make the R2 still seem like the best option.

Personally I would love that we could customize them, like an Astromech w/

1-B 3-A 4-I 1s in the rest and skills that will make it a Mechanic/Pilot/Slicer

What are the rules on this???

Because you want a custom Droid that has access to advanced skills and it seems like you want it to be more like an NPC attached to the party rather than just party equipment I'd suggest you build it as a PC and have it earn EXP developing it as any other member of the crew. Any Mods and added equipment are paid for out of the crew's credits and other advancements through EXP are skinned as the party mechanic's "upgrades". This will allow you to give the party more flexibility to customize the Droid's abilities, a greater connection with it, and keep the Droid at the same basic advancement as the rest of the party. Plus you don't have to create any special rules to make it work.

If you only want it to be an object that very occasionally helps out, then just buy a stock Droid and have the party buy upgrades that either the mech installs or a dealer does using the equipment list etc. as a base.

I have to admit. I am pretty upset with you all? How come no one, the entire time has told me there is a K9 Droid?!?!?!

This is utterly amazing.

http://starwars.wikia.com/wiki/Astromech_droid

This is the link my friend sent me about astromech droids

If you don't need the astrogration part, and just want a mechanic droid.

The MK series and G2 droids are also alternatives