Hey mate,
Firstly let me suggest you buy a Decent Panel filter Like a KnN or a BLITZ they will be legal and basically do the same job.
I bet all your friends have said dude get this and that, it will make it go better, WRONG. In Reality a POD filter will do nothing but suck hotter Air Into the engine, unless you also invest in a COLD-AIR intake then It might do something, but it will still Be very minimal. You will be much better off leaving the stock air box and funnel, the engineering of it its awesome!. Cold air straight from the front bar, Unless you want a FULLY SICK waste of $30 bucks, and a defect notice. Yes they are illegal unless covered.
Perhaps a change of spark plugs instead of wasting your money.
To answer your question, Use the search tool. This has been covered before, or just maybe buy the right size adaptor.
JUZ.