I did the modification to my 99' Box and I am quite impressed. It is noticeably louder after 3k RPM. It does have more pickup after the modification; at least that's my experience.
This website has a very good "how to" de-snorkel:
http://www.ppbb.com/boards/ppbbphp/showflat.php?Cat=&Board=ARCHIVES&Number=820409&Forum=ARCHIVES&Words=10min&Match=Entire
A couple of points:
1) When removing the snorkel I grabbed it and gave a quick hard yank, it came out immediately.
2) Make sure you push on the slats in the correct locations. That was the hardest part for me.