Its not starter / battery / Key because it cranks over.
I would throw a fuel ressure gauge in line with injector rail and see what sort of fuel pressure you have at the injectors. It's unlikely to be the cause, but it will confirm that fuel is ok. Another way to check is to drop the air hoses off tothe throttle body, open the throttle wide and spray aerostart into the plenum while they try and start. if it fires at all, even poorly, you have a fuel problem. Look at lines, injectors, injector trigger connections and the like.
You probably need to make sure your TPS and CAS are hooked up and look okay.
The most likely culprit is Spark. Pull a plug out, Clamp it to some hard area well away from the plughole, insulate it from earth, then have someone try and start it. Use a long screwdriver or something with an insulated handle to bridge between a known good earth - like a strut tower bolt, and the spark plugs outer electrode. Look for strong spark. If it's hard to see, or non existent, you have problems.
If thats the case, look at your coil packs, connections from coil pack to eart and positive and the like. Remove the coils and check the undersides for split cases.
Can only be one of three things, and one of those is a no brainer.
Fuel, air, spark.
