Review on Dorman Cabin Air Filter Retrofit Kit 259-201 for Cadillac, Chevrolet, and GMC Models by David Alexander

Really 4.5 stars: It has hints although the photos are too dark. The details are very well done, in fact the filter provides such a tight seal that it also makes it difficult to install AFTER you've attempted to cut an access hole. It's not difficult but very tiring as you have to get under the passenger side dash to cut the - apparently marked (the only place it belongs) - AC line. I used a Dremel type rotary cutting head, an oscillating tool with the blade set at a 90 degree angle rather than straight (otherwise the tool would have no clearance). Unless you are Hercules, FORGET what the instructions say about how to use it - the usefulness of a knife. HA! No way. Maybe after you start the hole with a drill. While this is a tedious and frustrating task (my dremel broke - I used the twist bit in my screwdriver), it's worth the effort. The filter is actually oversized and had to be stuffed into the hole and grouped, but in the end it was good, the sunroof hole they send is already in your dash! Behind is a notch for the other end of the hatch. Follow the instructions, take your time - you can do it.