It just depends on how much boost you are running. Im planning on no more than 10psi. Most of the time I am going to keep it around the 6-8 mark, so 550 will be plenty for me. But thats the great thing about having an ems, it for the most part doesnt matter what size injectors you get(im talking about bigger ones). You could get 1500cc injectors and tune them down with an ems. I wouldnt advise it but it could be done(unless you are running 30+ psi).

I was planning on running the AEM ems, But I just dont have the money. Plus the only guy that can tune h22a's around here to more than 5psi w/o blowing them up, uses the hondata. Im planning on going with a chipped p28 running the S300 though.