Nova... not everyone is bothered about the technical specs under the bonnet..they just want a nice good looking car and power usually comes with that......
Dump Valve keeps the turbo spinning between gear changes..mainly for fast gear changes as the air pressure in the intake system stalls the spinning turbo so by venting the intake the tubo keeps spinning,therefore taking less time to spin back up.... Lag is what happens before the turbo spins up...in others words you put you foot down and it accelerates like a normal car then the turbo starts spinning and the power kicks in... Anti Lag = boost in all rev range...