just to clear up the misinformation from StageaMang
The impeller is made from nylon, the rear from ceramic, you won't "melt" the nylon because its on the intake side of the turbo
if you get enough heat into the turbo tho, you will melt the glue that holds the wheels onto the shaft
a hypergear highflow is about $800, nistune + tune is around $1000, add a new fuel pump for safety for $200 and you can have around 200awkw for a decent price (assuming you have an aftermarket exhaust already)
i've put around 40,000kms on mine, driven from the gold coast to tassie and back twice, used it as my daily to get to uni and deliver pizzas and its been great
only things i've had to change are:
timing belt (100,000kms service, got a free waterpump with it so changed that too, whole kit was $260 out of the US! INCLUDING A GENUINE WATERPUMP!!!)
new radiator (top tank cracked, $220 for a kotorad radiator off ebay)
lots of oil changes (i change at 5000 kms because i use a semi-syn, but its overkill really)
new o2 sensor (only about $70 and most of them need doing anyway)
because of the parts interchangeability you can upgrade things really easily, and quite cheaply too
so maybe look out for one with a few things done to it already and same some $$$