Preperation for a turbo

thanks guys, if i sounded like i knew what i was talking about at any point then forgive me cos i don't! I would like to learn though and i figured this would be a better place (talking to people who've actually done it rather than just reading info on web sites)

oh thanks i didn't realise any 99-00 stuff would fit my engine. Is the SiR the equivalent of my VTi over there? or is it the SiR-II?

So, from the sounds of things, fuel and exhaust first yeah?

So...

Fuel: Does this mean uprating everythig to do with fuel supply? e.g bigger fuel lines? better fuel pump? bigger injectors i know, but what else? Do I want to buy a fuel/air monitor (like the Apex VAFC) before or after i get the turbo?

Exhaust wise, i keep hearing everyone say i'll need a bigger exhaust (3 or 4 inch), is that from the down-pipe all the way through? Would twin 2-inch exhausts provide the same flow or would it be more restrictive?

Another couple of dumb questions coming up... I keep hearing people talk about the header. is this what i would call the manifold? And I was going to get an Apex forced induction kit a few days ago but then I wondered whether this would be redundant when i got the turbo, would it be replaced or what?

Thanks again for the help and for putting up with me!