One thing to keep in mind is that the more you use ADAM and plasmids the less human you are turning yourself.
You really start to become a monster if your not careful.
The question is how does something like that play out for players? "Less human" at a glance really isn't much of a deterent to players.
My concern is how much should plasmid-tech put you ahead of the power-curve of regular players. That it makes you superhuman is a given, but the Spycraft/Mastercraft base line is pretty dang far above the norm. For every smidgeon you beat the curve, you need to be looking at tangible, and honestly fairly brutal drawbacks (if this is intended to in any way integrate with the core character options of either game).
That's one reason I suggested the tonics might be treated essentially as feats, but feats you can grab a level or two early. You suffer some setback (driving cravings for ADAM) until your body fully integrates the tonic in the form of burning your next open feat slot as your career level "catches up" with your power level (and the need for a balancing drawback fades).