alot of ways of acheiving this figure, but providing your engine is in good condition to begin with you can use standard internals and standard cams & CR; depends on how you want it to drive really

you'll need the following

t34 turbo with a .63 exhaust housing
-31 or -34 actuator
rs500 intercooler
decent free flowing exhaust
siemens blacks 83lb or bosch greys injectors
3 map bar sensor
grp a coil
suitable chip from msd or such like company
grp a head gasket

this alone will get you to around 400bhp ish

but you need to consider other things too, such as:

rewired fuel pump (direct feed needed from battery)
044 fuel pump (not essential but i would)
oil breather system (dump the kidney box set up)
decent clutch (ap 6 paddle clutch)
arp head bolts

ummm i think that's about it..i'm sure there's something i've missed tho......