A T40 torx key will get the cover over the coils off, and a T27 will get the coils off the mounting plate.
You need NGK BKR6EKPA large plugs, gapped to 0.9mm according to NGK or 0.7mm according to Alfa and NGK PMR7A small plugs, gapped to 0.7mm.
Don't forget to torque the plugs up carefully, 25-35nM for the big ones and 10-12nM for the small ones.
The whole job took me approx 45 mins the first time and there are no prat traps.
Ps Allparts do the plugs for £8.38 ea if you ask nicely, the genuine Alfa price is £20 each!