Here is an SPi manifold on ebay UK

https://www.ebay.com/itm/386086534752?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=Xke26tfWT5i&sssrc=4429486&ssuid=zawmNQ8WSC2&var=&widget_ver=artemis&media=COPY

I think Japan did get the MPi, but not all cars were fitted with it due to the aircon and auto gearboxes.

My JDM Paul Smith is an MPi block, but with a side radiator and SPi injection.

Dan, I believe Japan spec minis did not get the MPI. They come up on eBay often. In fact there is a set up 4sale on Mcgees site. 

A friend (not a member here) told me he has had a couple of throttle bodies rebuilt by MiniSpares for around 250 pounds each. He also found that Burlen sold new MPI throttle bodies last time he checked. (I'm a carb guy.)

Looking for sources for either a refurbished SPI manifold and throttle body....or just a used one that is no longer needed. I know they can be re-built, with new coolant / heater tubes etc., but rather than rebuilding my leaky one first, and possibly messing up and not having a functioning unit, I want to practice on a spare and see if I can do it well enough to swap it for the working (but leaky) one I have on my 98 mini. Any suggestions would be appreciated. Even suggestions for doing something different from refurbishing an SPI manifold. Thanks