Power for spec ?
 

Im buildin an 89 mx5 with t28 off an s14, 550 inj, duel feed FM fuel rail, fully rebuilt motor(stock internals), large FMIC and ally rad as well as a couple of other things but i need to know what ECU people are recomending , how much boost and how much power would i be hoping for with this set up ( using 99 ron unleaded, from the UK)

a true 60mm compressor wheel could supply a good 300rwhp. it will spool well and run well.

Megasquirt is the only way to go nowadays for simplicity and ease of tuning.
http://www.diyautotune.com/catalog/m...tpnp-c-40.html

If you're looking to get some longevity out of the engine, I'd say with your 99ron, you could run 15psi and for and 260-270whp for a long time on a newly rebuilt stock motor. By long time, I'd say 30-50k miles isn't unreasonable. Just don't get too greedy on the timing!

Your T28 can push more boost, but you're shortening the lifespan of the motor and tranny considerably. You also need to consider the differential. I'm not sure what UK spec Miatas came with, but if it's the 6" dif and you plan to drift, it will last about half a day before grenading.

unless you already bought the fuel rail.. may want to consider just tapping the stock one. Also, agree with what was said by SamNavy (aka Joe from family guy).