You only have two choices really mate, in that samco, or direct port, so i wouldnt worry too much about the holes as there isnt anything you can do about it really.

Make sure you (as i know you will but im mentioning in case others reading this dont know) angle the injector so that it "corkscrews" the fuel/nitrous mix down the inlet rather than pointing it straight.

I personally would mount it slightly further away from the TB, even though you will lose a few bhp due to phase change it will give a more even distribution which is more important as you can always claw that few bhp back with a bigger jet if you want anyway!


For larger amounts (i would change over after 150bhp), direct port is a better option simply cause it reduces fuel dropout, but then you get other issues like reversion which can lead to dropout anyway, particuarly at lower rpm, so its a bit 6 of one and half a dozen of the other!