Just keep in mind.
harness conditions will not be NEW unless you recently reoplaced the harness.
So from a time perspective you are looking at 21 years for an 87 and 16 years for a 92. That is a lot of heat cycling time and usually ends up making the wire jacket a brittle mess.
Now on to the standalones in question.
AEM is Plug and Play (PnP). What this means is that you take out your old stock TCCS and plug in the AEm and that is it. It is installed. On the other hand what PnP does
NOT mean is Plug and run the crap out of it. It is still a full fledged standalone so it requires tuning. PnP also does not mean that it is easy to tune. A tuner will find it simple enough but to think that ANYONE can install the AEM and tune it themselves is short of silly. That is where MOST of the problems appear from when the buyer thinks that because it was easy to install it will be easy to tune when it is nowhere near the truth.
The stinger is a good system (they all are).
The real question is does one provide something you need that the other standalone does not? IF they both do the same thing than the more pertinent question is, which system has more local tuners available that KNOW the system or if remote tuning is an option, how easy it is for the "remote" tuner to tune your car?
btw. Keep in mind that a dyno is nice but think about this. How do the Pro-stock. Pro-mod cars etc get "tuned" as their power level is beyond any dyno out there?
Think about that for a bit.....