how much power will i gain if i loose the power steering and how easy isit to revert to no power steering?
You would have to be mad to remove the pas. There won't be any noticeable increase in performance, and you'll end up wrestling the car. The car will be a pig to park lol, and you will feel the lack of pas at speed, especially when driven at pace.
The most noticeable place you'll see an issue is on long fast but sharp corners where an upchange is required, eg A3 coming through Hook and heading towards the Esher exit. As you leave the 50 zone and enter NSL you can start to accelerate hard and the corner is quite hard itself. In a non pas car you really do have to keep a firm grip when you make the up change, and thats if you make the upchange. In a pas car you don't have to hang on quite so hard.
With non pas you just don't have the confidence to throw the car round so much. If I could be inclined to get it on my 16v, I would without a doubt.