Absolute speculation but a little research on the possible engine and drive train for an imagined CX PlusFour comes up with the B48 BMW engine used in the BMW 2 Series Coupe 230i. It is available with a 6-speed Getrag manual or an 8-speed ZF automatic.

The B48 used is a 2.0 L I4 turbo with 185 kW (248 hp) at 5,200 rpm and torque of 350 N⋅m (258 lb⋅ft) at 1,450–4,800 rpm.

CO2 emissions are 135 g/km, a vast improvement over the current Plus 4 and could even be less for the Morgan which would be lighter than the BMW.

Perhaps a more likely alternative would be the engine used in the 220i: a 135 kW (181 hp) version that develops more than adequate torque for a Plus 4 CX platform alternative: 290 N⋅m (214 lb⋅ft) at 1,250–4,500 rpm.

The way that tax is being levied on the basis of CO2 emmisions this might bring the on-road cost of a possible CX PlusFour to the same or less that a GDI Plus 4 in the same way that it has made the on-road cost of a PlusSix in some countries less than the cost of a conventionally aspirated V6 Roadster.

I will be very curious to see what, if anything, Morgan have in the pipeline. I feel that there must be both a 4 and a 3 cylinder version under consideration.

The BMW 218i produces 100 kW (134 hp) at 4,500–6,000 rpm and 220 N⋅m (162 lb⋅ft) at 1,250 rpm. CO2 emmisions are a mere 133 gm/km in the BMW and could well be less in a lighter Morgan. When it comes to performance in the real world torque is what it is all about and this would give brilliant performance for an entry point CX Morgan. A PlusThree?

It may not be a Bavarian power unit they chose to use, Ford has a lot more history with Morgan cars, just saying.
I do appreciate the commonality of drive train etc etc..

I'd like to see the German flat six in it and that would sound nice too. Just a different sort of Plus Six that would appeal to the Hipsters.

I don't see another Ford engine...….Ford were apparently hard work on the 3.7 with what MMC got and the price.....which is why it took a long time to resolve the deal.

I'd imagine the CX chassis would be an easy installation for another BMW family engine - I'd wager there is a CX chassis car already being tested with a smaller BMW unit as per Peters suggestions.

All very interesting stuff and very likely to happen , I hope there aren't complaints about the cars being too ' perfect '.

The Ford 1.0 ecoboost is a great engine, we had a fiesta Zetec S with 125 bhp, I think it can be easily tuned to around 180 bhp or more. It also sounds fantastic for a small engine!. Have a look on YouTube at the single seater Ford at the Nurburgring. It's disappointing if Ford is being a little awkward as I think it would be a great engine for a CX based 4/4 or plus 4.
https://youtu.be/AM5HiDq2Unc

I would imagine the commonality of the BMW parts make many of the mount points interchangeable which would lead to a BMW 3/4/6 and gearbox combination. I wonder if that would also lead to a manual gearbox with the 3/4 pots?

I would tend to go with BMW options.
Commonality of parts re installation for one.
Also the new owners are likely to have a different attitude to change than the previous family based group.
Hark back to the John Harvey-Jones era......a reluctance to make significant changes at that time but some crept in later.
There is also speculation on a factory revamp. This could add to a lot more changes to manufacturing/assembly processes.
The attraction of a Mustang engine and the Cosworth variants gave an opportunity in marketing a sporty image but not without issues re drive ability ( rev hang and power and range).
I also wonder at the ability of the chassis to carry Hybrid/ EV options too.

If I understood from a few things that were said at the time of the CX platform launch Hybrid/EV was a definite part of the future project for the platform.

I suspect the electronics and bus/network architecture might be a key driver for a single engine supplier.