I just recently (like 4 days ago) replaced my stock air box with an aftermarket pod filter.
My 4 bolts were also not easy to remove, I used a socket wrench to get mine off, I found it ALOT easier using this than an open-end spanner.
Once I had the bottem half of the box out, I found I could lift the top half with the AFM up a little bit to get to the bottem 2 bolts.
One last thing, my POD is an HKS Super Power Flow, if yours is this too, be prepared to have an even harder time getting the nuts onto the stock bolts when attaching the new mount thing for the POD.
Hope some of this helps :-)