I had the same problem here tonight . Fitted a 8mm earth lead from the top of the strut tower to the engine block & she starts every time. cranks better as well

Can try going from negative battery terminal onto inlet manifold too .. I tried that when i was dealing with my electrical issues, but as some of you read it turned out to be a burned out brant alarm module.

Cheap thing to try out though for sure.

ive had the same problem for a while now, all i do is wait maybe 10-15 seconds after i key in the brant, then try and turn the key and works 90% of the time.
if it still doesnt start all i do is knock the steering column and it kicks over, primitive but it works

My key needs a love tap sometimes to start the car whilsts its switched to ignition...

Never had a car with so many issues as the WRX

Subaru Ossie had the car all day today and could not find a problem, they said it might be a sensor on the crank,(i don't know if that means the starter motor).They said there was two error's in the computer,they fixed them and changed the pin number to se if that helped.They also said if this happens again to tow the car straight to them,it would be easier to find the problem.

Thanks for all the feed back

Regards steve