is it worth fitting a dump valve on my 04 sti heard a lot on about them advice please...

 

Yes, a dumpvalve is an excellent idea on an STi.
That's why they come out with one as standard.
If you fit an aftermarket one, you void your warranty - and gain very little, if anything.

 

thanks m8 as you may have noticed my mechanical knowledge is little so if they all ready have one on why do i keep reading about others fitting them on here,and were abouts on my car is the dump valve if you can help .

 

People fit aftermarket ones because either the original broke or they want it to make a noise.

The original one is located to the front right of the intercooler (big black thing on top of your engine ).

 

A recirce valve will be better than an atmospheric one. If its the woosh sound you want then go for the atmospheric type.. if its performance you want then go for a recirce type.