You will get "turbo chatter" if you remove it, not a good idea as it will shorten the life of the turbo, or worse snap the compressor wheel etc, especially with higher boost.

The sound is excess boost being forced backwards through the pipework and through the turbo itself, it has nothing to do with the wastegate!

You won't increase lag, but if you can imagine without a D/V your stalling the turbo, so it has to keep "re-spooling".

As said just fit a recirc one if you don't want the sound (As Ford did in the first place )

Martin