Even if it was what I think was, then 270bhp is tops...
I reckon what happened was, the previous owner had the original turbo fail on him, he bought a unit off eBay or a online shop and this was available as an upgrade unit for the same price as a stock unit , so why not fit the bigger turbo... Some of these cheaper turbos are pretty good but you just have to remember you can gt them brand new for £300 ....