Well, I had my tank up doing some stuff so I went ahead and removed my snorkels. I got pipes comin and was going to wait and do this at the same time when I got it tuned but decided to see what would happen. I only went for about a 25 mile drive and, well, couldn't really tell much of a difference. There was however, no poping or backfireing or anything funny. What I did notice was the difference in sound...and I liked it. We'll see how it contiues. Anyone else done this as opposed to removing the whole top of the lid? I was told this was just as effective and it will get all the air it can through those two (2 5/8" diameter) holes anyways. Plus if you don't like it, this way you can reverse it.