The purpose of the pipe is supposedly to help get more air into the bay, since it's no longer being directed in in the same way as with the standard airbox.
As for whether it's genuinely necessary...I dunno. It's probably debatable whether a metre-length of bendy hose is actually helping direct cold air into the bay. And hey: if it turns out it's necessary, then you could buy that metre-length of pipe from a shop for, like, £1. 