Thanks guys. This was one of the articles that I came across. Found it quite useful as it was comparing which two turbos would work.
http://www.lovehorsepower.com/joomla...id=4&Itemid=88
The calculations I have managed to get my head around and are pretty straight forward. What I guess I am struggling with is looking at two compressor maps and think, ok this turbo a is better for me than turbo b. Is relying purely on compressor maps a good way to figure out which turbo is best, or should it be used in conjunction with other tools?