Garrett always have there name, or AIResearch stamped somewhere on the comp housing, although having said that I can't remember if mine does! Turbonetics do likewise.
Unfortunately manufacuterers of the cheap Chinese knock-offs also like to give there turbos similar numbers in order to ride on the back of Garrett. Be wary of the un-named Chinese turbos as they suffer from poor quality control. Not saying it
will blow up, just that it
might. They're easy to spot though. They generally look the same and have similar titles.
Did your turbo ad look like this?:
ebay ad Here's something interesting. Everbody will tell you not to buy Chinese turbos, but the vast majority are just parroting what other people have said based on 22nd-hand hear-say. However I found this thread dedicated to peoples'
first hand experience of them so you can make you own mind:
The Definitive Ebay Turbo Kit Thread