Thats why you need the Piston not a normal Dump valve.I've got the one recommend on the bailey site for the small turbo, they should know what works hopefully.
The recirculating type is just quieter thats all, it doesn't vent to atmosphere.
As Dave said the blanking plate covers the hole left by the standard one.The kit moves the dump valve to the cold side of the intercooler for reliability, apparantly.