First you will need to decide how much hp you are after.
You can upgrade the turbo, and manifold. BNR rebuilds and makes the OEM turbos into hybrids. Many people have had good luck going that route, and with a rtek chipped ecu, injectors, and exhaust upgrade.
I would suggest starting small and doing a compression test, upgrade the radiator, fix any and all pre-existing problems. Upgrading the turbo stuff properly is going to cost more than you likely paid for your car.
When you up the boost you will shorten the lifespan of your engine. If you do not know what you are doing you can dramatically shorten it's lifespan.
