I've done it to mine, and I'm quite happy with the results. Has noticeably more zip and quicker throttle response, from last couple times I've refueled has helped slightly in the MPG dept as well.
Ranger 1 reported that it's virtually eliminated his problems with a damp air filter after driving in the rain, and with sucking up dirt and road debris into the filter housing. He also stated that if you leave the water dam off in dry weather, you can get a nice ram air effect at speed.
Haven't checked my filter since swapping over, but then I haven't been putting that many miles on it lately - been too busy playing with my other diesel!
I believe the one thread where this was discussed at length was under "Wet Air Filter". You could probably do a search for "V6 airbox" and come up with most of the threads where this was discussed.