If you just want 200rwkw or 260rwhp approx
the stock turbo on .8 bar should net your power goals (pending on tune)
front mount intercooler (a generic one from justjap will do the job as china copies are proven to handle 500hp) $345
with piping
Apexi SAFC for about $250 (used) on ebay or the new Apexi NEO for $400(new) on ebay (most shops would charge around $550 figure) allow it 200-300$ to install and tune
a bosh, walbro or gtr fuel pump will do (not nessesary but for peace of mind if you like)
a good clutch and tyres would do wonders for drag times
stock turbo would be good for 260-280rwhp anything more then your just lucky or someones telling bullocks
when the time comes for more power your gonna need either a direct fit turbo on the stock manifold or a SS manifold (not that expensive these days 500$ give or take) plenty of cheap upgrades around from JustJap and KKR ($500) type turbos to HKS/Garret even a garret turbo would be around $1500 do dont bother spending 1k hi-flowing your stock turbo
afm, injectors, cams, full ecu will all depend on HP levels
engine should be good for 350rwhp on stock internals if serviced regularly, i know alot of people have milked 400+ out of the good old RB's but how many genuinely last long on high boost and regular thrashing?