If you search there'll be lots of detailed results on the topic... - but take note of warning above re MOT the job has been done many times but there is the theoretical issue.....
It's been a while since I did this but....above is about right for starters - you'll need a new inlet manifold with a vac take off for your brake servo - the MG metro inlet is about the best OE one...
I like using OE parts wherever possible - the electronic dizzy on the spi one is "dumb"a 59DM4 (rare) or 65DM4 (pop up on ebay regularly) but your coil will be fine..
My memory may be faulty here - but I don't think the spi cam has the lobe to drive a mechanical fuel pump - so I used a facet cube type (nothing fancy only 3-4 psi needed) with a regulator - you've already got an inertia switch in the spi loom (ended up swapping the cam to a 266)....