VTA DV's are sh!t, I should know as I was stoopid enough to buy one and now need to buy a decent recirc.they will put your fuel bill up and your car will pop n splutter more. ask around on here.
but they do sound cool.
you can buy mine if you want

edited to say.....not a great sales pitch (actually they make ur car realy fast and u can have mine for £5000)

[Edited by Dan_P - 10/5/2003 6:18:38 PM]

Have just bought my first impreza. Have heard paople talk about dump valves. Can somebody tell me what they are, what they do and if it is worth getting one?

Use the search to find out what your looking for. And welcome!

Put simply, what they do is vent excess charge air from the induction tract when you shut the throttle off. This prevents the air pulsing back through the turbo, which can damage it.

Recirculating valves divert the waste air through a pipe back into the induction system where it goes back into the turbo, while others (vent to atmosphere types) dump the air directly into the engine bay.

The Impreza is fitted with a recirculating dump valve as standard, and while some aftermarket valves use theoretically better designs, unless the standard one is broken or leaking, there's no need to replace it.

Most of the aftermarket valves available are the vent to atmosphere, and while many make nebulous claims for performance increases, their main purpose is to make a loud "pssssht" type dump, rather than the relatively quiet one produced by the standard valve. They can also upset the car's fuelling, which isn't really desirable.