it is a fair amount to do with the reputations of the companies. Garrett, HKS, Blitz, Apexi etc etc are all reputable and established companies that have a made a name for themselves amongst the Japs, US an UK markets. I will admit that Garrett units and the like are overpriced because of their name to a certain agree but you cannot defer from the fact they make quality products.

Other companies might be producing turbo's at much cheaper cost and to your good fortune you may find you may have a bought a solid turbo with no interntion of failing and serving you well in which case you would be very happy with your purchase.

However, I am more inclined towards the fact that cheaper turbo's are sold at a cheaper price due to the manufacturing costs being lower. So you might have an absolute shocker on your hands. It's that reservation that would play on my mind if I was to buy one.