I think de-snorkeling makes a HUGE difference. The car now snarls/growls and at WOT while passing someone on the right...well...I have scared the hell out of people in other cars while doing just that!
Remember...you will receive NO POWER GAINS from doing this and it will cost $0.00 to perform such a mod. On the other hand you can spend $300 and up for an "intake", receive the SAME sound, and supposedly gain 2-5 HP (although I don't believe it and still wouldn't spend that kind of money for that kind of HP). You will NEVER feel 2-5 HP increase anyhow.
Then theres the oiled air filter issue. Do a search and see how many people have lost their MAFs because of the oiled filter.
Wanna de-snork?!?! Heres a link:
http://www.xclusivecar.com/Porsche_Boxster_S_DeSnorkel_Mod.htm