Sprintex superchargers

Agree 100%.

Lower inlet temps, more power at the same boost, smaller package too. Pluste Sprintex is a "compressor" as apposed to a "blower"

The only downside is no clutch pulley being available.

I am definitely considering it when my SC12 is on its way out.  
 
As for the the Clutch pulley, it can be wired to the bypass valve? So when the supercharger light is on, the bypass valve is closed so the supercharger is "on" in the traditional sense?

Dave is still trying to get the SC14 to work for him which I won't be looking into. 
 
Other than that, the mockup mounts for the 210 would be of interest, would be best to draw it up in solidworks and machine it out of a block of aluminium. This could be sold easily for sure. 
The gilmer drive setup you've drawn up is very interesting as well. 
 
My aim is not to have most of amount numbers in hp, as the MR2 to me isn't meant to have the same power or characteristics as a BNR32, nor will it be as easy and reliable to produce 200HP+. Whereas the the GTR will push 300kw at all wheels with minor mods. 
I am after a modern age SC12 replacement and its benefits instead of looking at shagged units. 
 
Ogura is out as you'll need to buy a pallet full of them. 
Rotrex is out- different power delivery/characteristic to stock/all the bad points of turbos and superchargers combined. 
Eaton - way too big in physical size. 
 
Whipple Sprintex and Opcon Autorotor appears to have the same innards, so overall package will be compact. This is also something interesting of note.
 
Sprintex is still the most ease to source due to their availablility and close proximity to me. 
 
So basically more research is still required, fun times. 

Someone had already tried that setup in the following link
http://www.toymods.org.au/forums/engines-accessories-driveline-sale/66977-twinscrew-lysholm-supercharger-opcon-autorotor-2087-a.html
 
This guy has been developing a kit for a few years, literally..
https://toymods.org.au/forums/tech-conversions/7026-mega-supercharger-4agze-thread-using-twinscrew-charger-8.html

decided to have a closer look at his setup.
 
The placement for the outlet of the supercharger is towards the engine, his piping has extra bends that wouldn't be required if he had gone for the outlet facing out like the sc12 arrangement. It is also taking up extra room just to have it that way, kind of weird. 
 
Other than that, still haven't had any luck with a good sc12. looks like other options will definitely be required if people plan to run their sc car for years to come.