Finally started to de-restrict the airbox on my G and ive got a great little tip-
I've read how ppl have had issues getting the top pipe out and resorting to hacksaws, lump hammers etc, well this should save any extreme measures and most importantly grazed knuckles-
Take a sharp stanley knife and locate the side clips that are holding the pipe in the airbox lid (circled in red),what you need to do is shave off this clip with a few cuts,basically stopping it from holding the pipe onto the lid, cut it right down so its flush with the hole in the airbox lid so that it doesnt catch when you pull the pipe out.
Repeat this on the plastic on the other side of the pipe you're removing,and also on the smaller plastic retainer on the top of the pipe (circled blue).
With the clips all shaved off you can simply push the pipe right out, if it sticks, just cut a bit more of the plastic away,and bobs your uncle
Hope this saves some cuts and grazes