Ren has a dicepool of 10, Vinnum if he has the infiltration skill also (now he's boosted), and I also have 10 (plus modifiers in every case). I have a chameleon suit and thermal damping (rating 2), plus all the tools. And the rain should also work in our favour (given a natural thermal damping, plus confusing some sensors).
I say we try to find a weak spot where the sensors are either dummies and where we can enter the building quickly (when there's a gap in the drone coverage), then take out the spider and take control of the sensors. Then the rest can come in and we move up, leaving Fang in control of the sensors.
If I've counted correctly, security rating 4 + 3 sensors + spider perception (unknown, but let's assume 3 to calculate) will probably also be around 10 dice. We just have to see if we want to take full control of the building as that gives the defense +6. I would at least go for disabling security measures (+3) so the people without good infiltration stats can get in without tripping all the alerts as we can neutralise that +3 with our own modifiers (my rating 4 camera neutraliser should counter already a lot of the extra security sensors).
So we have 13 (or 16) dice against our 10, but with all our equipment (including tacnet) we can bring that to at least 10 (or 13) for them to 12 for us. If we spend edge we should be okay.
@Sichr: my calculations are correct?
Since I assume that Dr. Mengele upstairs wants SWAT to appear just as much as we do, as soon as we're past the outer layer we should be okay on that account.