http://www.armadale4wd.com.au/products/unichip.htm
Pretty much a little chip that they can solder into your ECU to get access to tune it, mainly done on V6 commodores etc when you want a slight tune. Think of it as a greddy emanage kind of thing.
For the cost of it to get some one to put it in and tune it, your better off just buying a Power FC or emange, never heard of any one running one on a skyline and probably for good reasons. Don't think it could take away rich and retard etc so pointless.