Why "up to 3"? I don't recall any such limitation listed in the book.
Saw that on the forums here, but I can't remember where. Something like up to 3 datajacks, and up to three antennae for noise reduction up to 6.
The only place where they've said "limit of 3" was for the Antenna implants from Chrome Flesh.
One of the Freelancers came back and said their intention was to allow people to get as many Datajacks implanted as they want, which is utterly pointless. If you can do that, you could fill 1.0 Essence with 10x Datajacks and NEVER worry about Noise again. At which point, why bother leaving home? Suddenly we're right back to basement hackers with no reason to tag along on the team.
For my money, The Control Rig gets wired to all the points of your brain that a Datajack would go, and then some. That's why it provides DNI, and since it comes with a spool of cable, it says "it's basically like getting a free Datajack." However, since it doesn't expressly say it includes the Wireless Bonus, then it does not. In exchange for the Noise reduction, instead you are getting the ability to Jump Into devices. Besides, RCCs get way better Noise Reduction anyway.
And since it's already connected to all those places in your brain, I personally wouldn't allow someone to add a Datajack on top of that. It's like trying to plug several different appliances into the exact same outlet. There are no extension cords / power strips for your synapses. Which is why I also wouldn't allow someone to start doubling up on Datajacks in general. Adding USB ports to your computer will not make talking to a single device any faster. The connection between your mind and the target doesn't try and go through all of those Datajacks simultaneously (which is what would be required if you stacked the Noise Reduction), it just goes through one of them, and then out to the world.