Stephen,
if you are looking for STI injectors i have a set out my car, covered about 10k!! []
Standard airbox will be fine for the level you are going to, mine handled 345bhp fine.
When mapping, as has been said, get it mapped with v-power alone and no booster, you have heard of the effects certain people have had in the past with mapping with booster in it.............bad det when no booster was available and they wanted to "push on". Unless of course you have a never ending supply of the stuff!!!