I just purchased a PR CAI and I am waiting to recieve it via mail. Well my question is when I make the hole for the CAI I want to know what you guys use to make the hole. I was thinking about using a hole saw. I imagine I can use a 3.5 inch hole saw. If you guy have any other ideas let me know. It will be a while before I install it because I am dealing with a rod knock. Read my post in the kill stories section. Thanks in advance guys!!!