Basicly, take the various chemichals that can be abused by humans that are allready cargo, and make it possible to 'mount' a unit.
-When mounted, it becomes perishable (at differnt rates)
-When it perishes, if you have another in your cargo hold, it is subtracted.
-When you mount a chem, for a set period of time (depending on the chem) NOT having it inflicts a negative penalty
-When mounted, some positive (or random) bonus is added
Cardimine: slight turn rate bonus (very small, but there). When you run out, between 2-8x (random amount, but more likely to receive a smaller penalty ) the ammount of the normal bonus is turned into a turn rate penalty. A longer 'withdraw' period is added ( a few days to a week) when you run out. Liquid Cardi would have a greater bonus, but also a greater withdraw
Tobbaco: Smokes are relaxing. The ammount of 'shaking' a ship receives when shot is halved by this. However it is doubled during the withdraw period (12hrs)
Wine (and other rotgut if added): you're drunk and just dont feel it. Ship shaking when shot is removed, and your turning rates become erratic. One moment you may be turning better than normal, the next worse. During the use and withdraw period, your sensor ranges are reduced.
SynthWeed: You've got a hankerin for some sunbucks and twinkies.......... due to the relaxing nature of this intoxicant, you recive 1/3 of the shaking from being shot you normaly would, and while in withdraw must keep food items onboard or else your turn rate is reduced slightly