The raw says it all wireless bonus states rating one noise reduction kinda doubt ratings from same sources stack RCC noise reduction signal scrub vector filter even antennae yes they stack but three data Jacks no and if you want multiple connections just get a universal data port jack hub course now I wanna know if you can run smart link with old school program translator and still get the +2 dice pool bonus
You may doubt and you may choose to do as you wish at your table.
However, the develepors have confirmed datajacks stack.
And I do not believe that RAW limits how many datajacks can stack.
Is this overpowered- I'd say yes if there weren't so many other things that reduce noise, including clothing material.
As to your second question- if I'm reading it right, you want to be able to use throwbacks not wirelessly and get the +2DP...no-smartlink requires wireless now. It changed, Why? Because, Bunnies, bunnies, it must be bunnies!! Or maybe midgets… (Magic, that's why.)