Do you need to run a dump valve?

Reason being I have just fitted a front mount and love the way it chirps through the air filter!

I would like to run without if poss so I don't loose the noise

 

Depends what turbo you have. Not recommended with the VF range as the turbine blades can be damaged.

The dump valve is there for a purpose. It releases the pressurized air when you take your foot off the go pedel. This prevents compressor stall, which is when the pressurized air which hasnt been released, comes back through the turbo (hence the noise) and slows the tubro down, so when you put your foot back down again it has to build up speed again before you get any boost.
If the air goes back as far as the MAF it could give your ECU false readings too.
If you like the sound, go for it, but just be aware it may have a detrimental affect on your cars performance. I know some people have done this with no negative effects but for the above reasons, I wouldnt.