A few things spring to mind... Check all the connection to all the relevant sensors, one may have been disturbed while fitting the new MAF and plugs. Does the "injector" ECU fault light extinguish on the dash as normal, if not then you have a sensor fault and need the codes read.
Have you fitted the new MAF in the correct flow direction?
Check that you are getting fuel, Remove a front plug and check to see if it is wet with unburnt petrol... If not try resetting the fuel cut off switch.
Is the fuel pump charging(whining) as normal in MAR position? If not check the relays for fuel pump and electronic injection (are they clicking ok?) remove, clean the connections/ terminals (in front of the battery)
Did you double check the gaps were correct on the electrodes of the spark plugs before fitting?
Check the security of the connections to the coil packs and injectors it's easy to forget, trust me , I have done it
Check your throttle butterfly, is it stuck or not moving... The car would still start up but run rough without the rubber belows connected if the butterfly is operating properly. Get a helper to blip the throttle while trying to start, just to check.
It could be your crank position sensor playing up although I doubt it as it would occasionally refuse to start prior to what you have changed.
Check the engine loom for breaks wires can become brittle with age and pulling and tugging at sensor plugs can often break them at weak areas so best to check continuity with a cheap multi-meter.
If there was an underlying fault previous to the work you have done so far, once an ECU reset is done it can be too far out of values for it to start.
It isn't making strange/different noises when turning over is it? Remove the upper cambelt cover and check the belt for tension and condition... Check the teeth some may have stripped so timing may be out ... I hope not
I can't think of anything else to hand mate
Temperature senser unit??? With you saying it would cut out when cold????