Since I've read a lot of opinions about removing the snorkel and I thought I'd share some recent dyno results I posted on my site. I had my 2008 Ninja 250R dynoed, keep in mind it was bone stock. We did a run (in black) first, then another with the snorkel removed (blue), the red run is with the TYGA full system.
As you can see at peak it gained 1.5HP! It smoothed out the power, and while it doesn't show it, the stock A/F was really rich from the factory. The snorkel evened out the A/F although it was still rich.
Detailed report: http://racingorder.com/2010/10/tyga-ninja-250r-race-exhaust-system-dyno-results/