Well for 30 bucks I supose it worth it. But if it were full price its a waste. I've dyno'd my bike with, without filter and one with the paper element removed but the steel screen still there. Each run was within 1hp of eachother. Aftermarket airfilters won't do a thing to your 919. But for 30 bucks you will never have to buy another filter ever again, which is why I supose it is worth it.
02 919 (RIP)