No probs - am running a dump valve and cone filter on my Stg.3 4x4 Saff - get the whoosh at low boost but good strong chop of air back through turbo when foot down. Not really thought of trying it without DV - may give it a go but seems to run just fine as it is. Worth knowing from various posts and opinions on her that it appears no more detrimental to the turbo to run the car without....