I have 2 DV30's sotting in the loft. First one started sticking once the car got hot so I sent it off to Bailey to refurb it, done the same thing when I got it back. So they sent me a new one, but it done the same too. Only way I could get them to work properly was to run them upside down boost into the bottom).
Now running a Forge 007P, such a better valve IMO. Sound is nearly identical. If you want more noise fit a open cone filter.