Okay, here's the run down. I've got five players in my campaign right now. Two weapons specailists (one melee and one range), an AI, a mage, and a technomancer. Right, now they're preparing to go up against another squad of prime runners who've been doing some nasty things on behalf of the main villains of the story. However, I'm conflicted on how to create prime runners that are both challenging, but not so badass that they'll kill my players. So far, the players have been pretty well in taking out my NPCs, but this is supposed to be their real challenge since they've only fought small time freelancers and gang members thus far. This is supposed to sort of be a glimpse into the challenges ahead as the story goes into its third act. So, please, can you guys give any advice on properly creating these prime runners. My first thought is to just take the premades in the core book and tweak them a bit. However, if you all got a better idea, please let me hear it. Input greatly appreciated.

I like the pregens, but you need to add a lot of flavor so your characters don't immediately recognize them. ("Oh looks. she's the Ork Gunslinger Adept!") I.E. change metatype/race/gender.

Also, Knassers' got some great ideas.

Strategy. Tactics and Personality far outweigh any mechanics in building opponents. Mechanically the opponents are the handful of dice you toss behind the screen.

On the other hand, it's fun to build Prime Runners.

My suggestion is to consider what is a viable dice pool, and then figure out what cool stuff the Prime Runner has to justify having it.

This may get me hate, but a possessed character is a challenge for most. Possess someone the players are NOT to hurt and they may need to think outside the box.

AI's are a little underpowered, a good hacker could rip one apart but the AI would just "re-align" so there isn't much worry about death there.

It may seem cheesy, but look at their characters and make a similar team. Maybe make some changes like make the mage and awakened spirit (be careful of power level here!) or lower a stat or two to reduce the chance of death. Basically throw them at themselves, then it's all down to tactics (and dice luck!).

I agree that the best way to go about this is too basically double the characters with some minor tweaks to make them different in a more challenging ways. Like with the up close in your face combat character make the challenge to him use a different type of weapon and change some of his stats (like if the character is more speed use muscle or vice versa). For the Techno make a old school decker hold over, a guy that still remembers the days where the 'jack was the drek! Probably Elven in nature you know like the guy you always saw your old school hacker to be (at least for me). etc...

The best part about making these types of NPCs is that they can work out to be reoccurring... if any of them get away they could turn out to be the type that go out and get new pieces for the guys that get offed and what revenge against the players for many more acts to come!

Also, bear in mind professionalism. If the other running team were paid to do their task, it's really not good for the team to go in and kill them 'cause work is work. If they are willing to throw lethal force into the mix, don't be afraid to yourself! Players need to learn and a narrow full burst to the face with a lmg usually shows them the error of their ways.

I was going to suggest the clone thing too, so I'll just add don't forget to give them goatees. You can't have evil twins without goatees. This is especially true for the female pcs.