Got this tips from HKS Site which is great for everyone, the reason i post this some people thats is new to turbo doesn't know what to do on their first upgrade like i did,and i learn from every single upgrade mistake i did on my ride kih kih kih so here it goes.
By replacing the stock air intake, The Spark Plugs and the Exhaust into aftermarket ones. but what brand? well its up to you and your budget, if you wanna go buy new one or use aftermarket, the choices is up to you.
Next is the electronic stuff , the boost controller and the ECU, where nowdays there are a lot of choice in the market and some are cheap . same as the above no matter what brand it is, if its come with a plug in for your ride that will be great. the main thing is as long the dude is an expert tuner in tuning the ecu you just bought and that whats count the most.
and lasty is by replacing the Fuel Pump,injectors and bigger Turbo. if you are not sure on your modification is increasing Horsepower, bring your ride for a dyno test,over there you can see the result on how much your performance increases.
that is all, you may continue on drinking your heaven and earth Green tea or teh tarik halia which ever you may like.