Well ... figure the Dodge and Alfa are basically clones, except the Alfa has a bunch of expensive lightweight parts and the Dodge does not, the suspensions are tuned differently (springs, steering response, and such), and the Dodge is set up to use American engine oil; then Marketing changes the performance specs slightly, giving the Alfa a more revvy version of the engine with more peak horsepower and Dodge a bit more torque (but not admitting to it); different programs for the transmission, but the same hardware; and of course different dashboard graphics in roughly the same layout, to save $$$. The Dodge could keep the Jeep Compass' dash, while the Alfa gets its own, alternatively.
Pretty much that, although the dashboard and other visible parts will be unique. These are actually pretty cheap and easy to change within the same architecture (and allowing this customisation is kind of the whole point of the Small-Wide architecture family). Switchgear will be common. Instrument layout will be different, for branding reasons, but as the instrument binnacle is entirely software-generated, this is a zero inventory cost.
On performance, a lot of it is down to the mapping of the throttle input from the accelerator pedal; there’s often no need to change the engine programming at all. Similarly, with electric steering systems (which these have), you can achieve both the Alfa’s signature short-rack quick-response and a more American style straight-ahead bias with very little hardware change. Brakes would be one area where you could see difference in available hardware.
The Hornet/Tonale 1.5 engine is from the GSE family, which is not as fussy about oil as the MultiAir FIRE 1.4 engine was. Both will also achieve their EPA mileage with low-octane fuel, and while the Alfa manual may end up quoting a higher power output when using premium, the same would be true of the Dodge with a small chip-tuning. Coupling this to a PHEV also gives a lot of leeway for tuning the off-the-line performance in order to differentiate the brands further.
It really did surprise me that as flex manufacturing made it easier to do different cars with the same foundations, FCA chose to make each car semi-unique. Except, of course, when they didn't, like 500X/Renegade.
What FCA is doing is basically the same outcomes as flex: within a given architecture (e.g. Small-Wide), everything under the hood is pretty much in the same place in each model, although the exact part that you find in that place (or even if it’s there!) can differ between models. Where FCA’s approach (and PSA’s, for that matter) steps back from flex is in ditching the idea of being able to chop and change model type at each build slot: given how cars are bought and delivered (especially in the USA where bulk ordering is the norm), there is no meaningful benefit to being able to do this “live”, compared to changing less frequently.
Given that Belvidere was able to build any of the CUSW cars simultaneously (except Pacifica, which is too big), the decision to limit one factory to one model in the USA seems to be purely an operational one, and I suspect is about getting better pricing from suppliers (complexity and variation of parts inventory costs money). It also reduces training costs per site.
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@Cleffy - the battery type is Lithium Nickel Manganese Cobalt (“NMC”) as used by almost all EV makers except Tesla. This chemistry is still a Lithium-ion type, but is far less likely to catch to fire, and much less dangerous if it does, than the Lithium Nickel Cobalt Aluminum (“NCA”) cells used by Tesla.
