What is this attached to the standard airbox?

[focus_7]

As the title says, what's this black reservoir type deal on the airbox. It appears to have a vaccuum attachment at bottom and an attachement for something the size of a radiator hose at top.



What's its function, do I need it, what affect will that have if I delete it etc.

[dove grey 64]

It's there to cut down intake noise, the snorkel has a hole in it that links up to it.
Safe to ditch it, I just bypassed it as you loose air flow for no reqson

[focus_7]

Cheers mate, consider it deleted.

[Sam-Q]

that's a resonator housing, to remove harmonics from certain parts of the engine rev range. As above it's noise only.