Now, these dont come up for sale very often,
so you might find interesting to know, there is a
ME221 PnP ECU
for Mazda Mx5 Miata NA Mk1
up for sale, used but in perfect working condition.
This sophisticated Engine Management is the one most
tuners use these days for their 89-95 Mx5s with the 2 plug ECU.
All info about it can be found HERE
Price is a bit of a bargain, at
450 British pounds plus postage