Starting at page 378, you should find some very useful information in regards to basic grunts, guards on runs.
Here's thing that stands out in my mind, a professional criminal should not be challenged by basic rent a cops or two people walking a patrol. They're going to be as if not more skilled, potentially specialists in their field and very capable at what they do. It just so happens rather than more legal means to make money, they prefer other means.
Shadowrunners in my mind, fit into the category of specialists, who are capable and educated, if not academically, in some very specific skills and professions.
On some level it's the SWAT teams and the like that should threaten them. That for a Run to be a success, the team should get in and out without triggering a team to come after them. That any significant use of force against them is a failure.
In terms of stepping up a threat, challenge, I'd probably do the following, rather than give them more meat, metal, to shoot at.
Redesign the building, add in more passive measures of security, things they have to get around, making points harder to get around. Pressure plates, security systems, laser systems at doors, older style key locks in highly resistant doors. The old bank vault door in between you and what you're after. Even creating more points, processes people have to go through to get into the building. That they need a key, but they also have to apply for said key in the first pace, with a SIN and valid employee access ID. That shifts are very carefully watched and just sneaking it might be very difficult.
Active measures might be things like..... the company has paid for more regular Knight Errant and Lone Star patrols to go by or on a set schedule. As well as that they might have a more subtle security presence than everyone in a uniform. Perhaps some of the office workers are part time, the rest of the time they're sitting at a desk with a 9mm, 10mm on the hip. Don't rule out drones either. Buildings could have swarms of mini and microdrones as part of their security network. That while there is a flesh presence, the drones allow them to be applied very strategically.
Personally speaking, I wouldn't have a lot of technomancers and mages in corporate security on the same reason I think that designers need to really sharpen up their world on a whole. They forget that specialists who not only require specialist grade pay, are also quite limited in numbers. More so than they would assume. That if you do have a finite pool of such specialists, they would go to black sites, high security locations first and foremost.
I suppose if there's anything I really want to say on this, it's be cost effective with your security. If you're only going into a warehouse, is there any reason a dozen drones and half a dozen cameras which are hardwired to a server isn't enough security? Why should every run have physical security? That a very meat, lack of technology team, can not be challenged by needing to get around complex physical, technological security. Two people in the right situation can do infinitely more than a dozen, a grosse in the wrong one.
I think a rigger with a few, half a dozen drones, are the best additions you can make to a basic security force. Only one or two of them need to be for combat. The others just for watching the area, following the Runners about.
Take a step back and a more holistic approach to building security, it should be first and foremost, cost effective. Secondly, effective at its stated goals, thirdly, have back ups and secondary systems.
