Hi, I'll try and see where mine goes. The pipe is used to open the flap when the electrics allow it to be opened at 4500rpm+ so if you are removing the flap it is not required. The trouble is you will be losing vacumn pressure as the end of the pipe is not left in place or plugged closed. I think you will lose some power because of this (I'm not totally sure but hopefully someone will correct me if I'm wrong).
.Richard