Came highly recommended from many people as a good way to fend off sludge. Great price, easy to install (I found instructions online, it's not as obvious as one might think). Hardest part for me was unbolting the old vent box because I have a sub-frame brace on my 9-5. Other than that it's pretty easy and gives you some peace of mind.
Rating: [5 of 5 Stars!]