My contribution:
And for a useful tuning tip with your Mazda MX-5 based kit- try one of these...
...weighs 4kg less than the extant 4-banger and produces 200 ftlbs of torque low down- bolts on to a standard MX-5 gearbox- just needs an induction system that doesn't foul the bulkhead like these throttle bodies or bike carbs- a real no-brainer if you ask me.
Get one from a Mazda MX-6, 626, Xedos 6 or a 24v Ford Probe. Apparently the ones to go for are from automatics because they have limiters fitted and won't have been thrashed.