If I had this sort of thing, I might go down the same route that "cyberpunk 2020" did with chipped or artificial skills:
their was a limit to how many skills you could have articially enhance at once. in Cyberpunk it was limited by how many chips you could have in you at once, but some other mechanism might be used for non chipped versions.
they were only available for lower skill rankings, and the cost rose fast towards "impossibly expensive" as the skill rank increased. getting a chip that lets you drive a car to "just passed the test" standard is reasonably cheap, but getting a chip that lets you drive to "average Formula 1 driver" level is ruinously expensive... and you'd still not be the best driver on the track, because their simply isn't a chip able to give you a Lewis Hamilton or Michael Schumacher level of skill.
chips needed to be tuned to the user, and couldn't be hot swapped between users without a reset (so you can't just passed them round the party). the user must spend some time practising the skill after acquisition. its all well and good having every move in karate downloaded into your brain, but if the master your copying is really flexible and 5'8" and your 6'2" with all the flexibility of a brick, your going to need to spend some time adjusting to the difference between your "artificial" memory and your actual body. I think it was something like 1 week per point of skill above your own level, assuming you were practicing in your spare time.
the artificial skill overrode your natural skill. if you were, say, gun combat 1 (pistol), and picked up a gun combat 2 (rifle) chip, you couldn't stack them and have gun combat 3, and your speciality was rifle, not pistol (ie your GC (pistol) was now 0). If you put, say, a Pilot 0 chip into a character with Pilot 3, he would drop down to pilot 0 until he took the chip out, as even though he "knows" better than the chip, the chip overrides his knowledge.
because the artificial skill overrode your natural skill, you couldn't practice or improve your natural skill while using a skill booster chip. basically, you weren't "learning" while you had the chip, just doing what the chip told you.
their was a few flavour comments to the effect that while skill chips could get you the task fine, as long as your doing things the chip programmers anticipated, but they didn't let you improvise or adapt to changes very well. if at all. the enemy throws a standard karate punch at you, you react with the standard block. the enemy throws a "trick" punch he learnt in a back ally somewhere, and you still react with the same block, even though it might not work against his "trick" punch, because you cant adapt the chips programming. in short, "chipped" skill looks really good until it comes up against someone with "real" skill...and then fails hard.
in short, it was good for picking a basic ability in a rare or situational skill (for example, gun combat 1 for a scientist or medic type PC, or a rare knowledge subtype), but it was better to have natural skill in anything you felt was a "core" skill.
