You can find out a lot about a new car with a little spare time and access to a dealer ordering computer. One is that the V6 may no longer be offered, as the code previously used for it reportedly comes up as invalid in the computer. Losing the V6 wouldn't be all that surprising, since the 2.3-liter EcoBoost turbo four sits just about right on top of it in terms of output and overall performance. Ford actually downgraded the V6's power so it wouldn't completely step on the EcoBoost's toes and would therefore give people a reason to pay more for fewer cylinders. Dropping the six could mean a (mild) price increase for base Mustangs, as the V6 is currently the entry-level engine below the EcoBoost and the V8 GT.
The automatic transmission will reportedly switch from today's six-speed to the 10-speed that's being used in the new Raptor and some other F-150s. This is a logical step and should improve both performance and efficiency, assuming it's geared properly. A dual exhaust is going to be offered, although it's not clear on which engine or engines.
And then there's the news that the magnetorheological (MagneRide) dampers used on the Shelby GT350, or ones like them, will be available on the EcoBoost and GT models as well. Moving the fancy suspension down to these models is a very good thing. There's also something called Performance Package 2 listed as an option, which we can only guess is like the Performance Packs available on the cars now, but more. The EcoBoost Performance Pack gets you a modified suspension, different wheels with summer tires, and beefier brakes, while today's GT PP comes with Brembo brakes and a Torsen rear diff. So maybe Performance Pack 2: The Enquickening adds the adaptive dampers, perhaps with a unique tune, and that dual exhaust for some extra power? Just spitballin' here, but it sounds good.
We also believe a Shelby GT500 is in the works, but it seems like that one will come toward the end of this generation, in either 2019 or 2020. It's probably going to have a big wing and a lot of power. It probably won't need a Performance Pack. And it is rumored to be getting a dual-clutch transmission.
Mustang6G has more details on the 2018 Mustang changes – including new colors for the regular cars and the Shelbys – so check their post and forum for the full story.