Hello.

Ephedrine was commonly called 'Mini-thin' as that was the most common brand, is available, the courts have ruled that since the stuff itself is not against the law it can not be regulated in this manner.
Not that it matters, ephedrine itself is easy to produce.
The only difference between a regular aircraft and a mule bird is the 1030/1090 MHz RWR and how the transponders are configured.
In a common aircraft there is but one transponder and one antenna mounted on the belly of the aircraft.
In a mule bird there are 2, a gain type mounted on the roof antenna with a transmit disable and audible receive transponder is added.
Rural America? you bet! Texas ranchers are big time involved in drug production.
Nobody steals cows anymore, why? drugs are less trouble and FAR more profitable.