well... i have done the deckplate mod and appreciated the sound and increased airflow.... i find that the snorkel just generally makes people look....
dont get me wrong, its great to have if you drive down dirt roads following someone or go for the occasional dive in your truck. its also good for a cold air intake... the air up there is colder than you can get in your engine bay and plus, if you have a sun roof, you will love getting on it and hearing it sucking in air... the only reason i got a snorkel though wasnt to increase performance, i just wanted to know that if i met a hole that was a little deep, that i wouldnt lose my engine because of it. if you just want performance, go with the deckplate mod or a cold air kit, if you plan on heavy offroading with LOTS of water crossings then you should get the snorkel...