Hi,

What do they do, How much are they, and are they easy to fit yourself. Apart from a cool noise, what else will it do that the std one wont?

 

Make your car run rough basically, hesitate at certain revs unless the correct spring is fitted and you get it re mapped, otherwise pop and bang and sometimes flames, rich fuel, affects air sensing etc etc

I've just took mine off and refitted the standard re circ valve - much better, no noise

Please yourself

Steve