Discussion on:

'hyMOD' lets driver swap out either electric or gas engine

I am not sure why we need to over-complicate things?
now days when microturbines are advanced enough to be light and afordable
why do we need to make modular car is a good question to ask.
create an electic car (fully electric with motor-per-whell design) add a microturbine with a choice of liquid or gas fuel (or both as in have a gas tank and a space to mount a CNG tank) and be done with it.

micro turbines can use a varaety of liquid fuels AS IS, no special adjustments needed.
they are clean and efficient. and if you your desin right they can be made removable so if you only drive a shot distances just remove the turbine and do not fill the tank.

everything else is just an attmpt to siphone the money from the public.

The concept of the hyMOD is, Mary, intriguing but... as both you and vbp1 say, complicated and expensive in the execution. vbp1's idea of the permanently installed microturbine is far better. As for the hyMOD concept, what would be wrong with it being more user friendly and convenient, as well as more economical, in that the engine/battery swap be done by the owner, should they want?

well I guess with the normal engine it is not for casual user to remove and swap. you need tools and place to work at.
also you need to store it properly where if the engine/batery pack is rented
then it is not of your concern.

but with microturbine design it might be that easy.
I saw reports of new MT that are under 500 lb in weight and the sise of a laguage box. with proper design it might be posible to make a quick connect/disconnect system that would alow most (not all) users to remove it from the car if you wish to do it.but I think most people would just let it ride.
under 500 lb is not a big deal to have a peace of mind.
and no range issues.

I am not pushing the microturbines but it does make sence.

here is the link to a concept for an in-wheel motor by "Protean???s "
that you can couple with good on board generator

"http://www.smartplanet.com/blog/thinking-tech/innovative-motor-lets-gas-powered-cars-go-electric/6940"

Every small turbine engine I've ever looked at were extremely expensive to buy, plus they have to be rebuilt at something like every 2000 hours of use, which is also very expensive. Then there's the problem of the hot exhaust that you can't just blow out the rear of the car like a piston engine.
If the turbine is going to be used to drive a generator then there's not that much of a problem, but for direct shaft to transmission applications the turbines are way too sluggish to develope power, like "Tubo Lag".