I don't have the books in front of me from my work desk, but the weight doesn't change really to do a Narc and a ton of ammo, which is a LITTLE light, but not unusably-so.
I REALLY like this idea and wish I'd thought of it myself.
Same crits, same mass, it's about as easy a refit as you can get :)
It's one I've been preaching for, oh, /checks calendar, 34 years now?
Most of the "electronics" (BAP, ECM, TAG, NARC) are woefully underrepresented in TRO:3050.
I mean, we got the Raven (or should I say, the CapCon did) and then there are a couple NARCs for the FWL/FC on fairly slow platforms for the most part.
And outside of that, you see next to nothing.
An entire TRO of new toys but it really ends up being a bunch of XLs/Ferro for the most part.
Which is not to say that stuff like a "Griffin" needs ECM. It doesn't.
But there really should have been some options out there.
Like the Ostscout-7K is often criticized for having no guns, but myself, I've never NOT gotten good use out of it.
Random ideas........
Avoiding the super common bug trio since well, they are literally TOO common for the sprinkling in of support electronics.
Javelin w/ NARC as mentioned above.
Spider that goes w/ ECM instead of Pulse Lasers.
Jenner w/ BAP+C3S instead of SRMs.
Assassin w/ any 1 item (ECM/BAP/TAG) in place of SRMs
Cicada w/ TAG
PhoenixHawk-2 (This is 1st SW canon, but needed to be brought back sooner as field refit)
Trebuchet-7M variant that keeps the NARC but goes the S-Route w/ SRMs & more Armor/Heatsinks/Ammo)
Cyclops-11A/C - I love extra armor/ammo but how does this thing not have ECM/AMS too via Heatsinks or the SRM going away?
Anyway, those are just a few ideas I've had specifically centered around some of the less "common" models to allow for a trickle of Electronics similar to how the LC added some to the Firestarter for Battalion level support.
I also focused on faster platforms for the most part, where you generally want those items used.