Thanks for the info guys - after taking the airbox out to install a K+N filter element, I see how just taking the honeycomb out will make a big diff.
I can also see I'm gonna have to work over the stock airbox and intake pipe too - that's ridiculous - on the xtremes the hole cut in the cowl / core support is mostly covered by a piece of plastic from the headlight assy. The intake pipe for the airbox is approx 2 1/2 inches there, making the actual functional diameter around 2 inches. After I get done 'glassing over the ribbing in the top of the airbox, I'll probably replace the inlet tube with some 3" exhaust pipe, and open up the sheet metal a bit as well. :evilg: Some engineer needs to have the smacketh layeth for that one. :bash: