How long do would you plan to make the effect last to balance for the resources required to make it?
If you want to make enemies, try to change something.
stealth boy would be a nice comeback of this long forgotten valut-tech gadget and if it worked on SEC that would actually balance the stuff. Roachor I think here come alt's - your one charater would make stealth boys and sec for the sneaking one, isn't that obvious?
This is a terrible suggestion and would completely destroy sneak characters. 120 science means that you either have sneak around 280 and nothing else has points into it as well as forcing you to hold ammo and a stealth boy further lowering your sneak due to weight.
You don't have to craft it yourself. Your BG probably can't craft 5mm AP, your EW probably can't craft MFC - that's the way it is. The point is stealth boy could be made by explosives expert, which most sneakers already have to supply them with nades. And 1-2 kg reducing your sneak value? Oh, come on...Anyway, there's nothing terrible in this suggestion - I think that actually nerfing sneak (ie. making it less effective than it is) would be THE terrible thing. To be honest, I posted it so that all those "it's a magic spell" and "lol he's 13 hex away and I can't see him lol" crybabies would stfu already The only thing that'd really change would be the fact that dying would actually cost you something.
I like this, but id like to preserve sneaking without any device required, somehow. But it needs serious balancing of course