Ares l85a2

[FLAK 01]

Hi there I just bought a ares l85 which arrived yesterday and the label on it says it was tested at 133.9m/s, which being rather new to airsoft and this being my first gun I assume that m/s is meters per second which works out to 439fps which is waaayy to hot for the uk, however being my first gun I am not wanting to just tear it open. I have been told that ares have a quick spring change I did take the upper receiver off last night and could see a twist cap on the back of the gearbox behind the butt plate is that the quick spring change? also I seem to remember somewhere that you can lower the fps by clipping the spring is this true or must I buy another spring?
Also somewhere I read that some ares l85 where fitted with a tight bore in the factory is this true? How can I tell if it's a tight bore?

On another note I'm wanting to get a susat sight can anyone recommend any good replicas or is real steel the way to go?

Sorry for the silly questions and thanks in advance for any help/ info.
John