You can desnorkel an '03, but it very different from the pre '03 snorkel with the integrated cup you see pictures of in all of the desnork threads.
The process is largely the same, though - and you have to pull harder than you think could possibly be reasonable to get the thing out.
Removing the snorkel did made an audible difference on my '03, but not so much that I'd portray it as the semi-orgasmic you-gotta-try-this mod that the pre-'03 folks make it out to be.