The only bit of custom work we encountered was the need to shorten one of the PCV tubes. The instruction book includes detailed instructions on how to do this, but it basically involves cutting the tube away from the plastic quick-disconnect fitting and then cutting the tube to the correct length. Next, heat the tube with a heat gun (don’t melt it!) to soften it enough to slip the quick- disconnect coupler back in. As the tube cools, it forms a tight seal around the base of the coupler. This sounds more difficult than it actually is.