Just got one from the UK, there are 3 different springs, a red one, if I remember correctly a green (or blue??) one and the one that is fitted at the moment. Which one must one use on a MY00 WRX STi??

 

Have alook at this thread. http://www.scoobynet.co.uk/bbs/showthread.php?t=302954

 

Thanks mate, but thats atmospheric, mine's a recirculating one

 

And...? The springs are the same colours

 

Ooops, silly me

Another stooopid question, whats the difference between running a softer spring and a harded one??

 

Basically the softer one allows the "dump" to happen more easily. Having too soft a spring can make the car hard to control if you are trying to feather the throttle mid corner. The engine goes rapidly from holding boost to dumping and then back to holding etc. In my car I use a blue spring with 2 shims as, for me, the blue is a touch too soft.

 

Thanks mate, I really appreciate your input!

Do you know where I might find the instruction for fitment or a diagram online??
I have received the dump valve with the springs/shims but no instruction manual/diagaram. I dont have a clue on how to go about it!!

Also, the spring that is fitted at the factory, is it somewhere between the blue & red one as far as hardness goes??