Thanks man, Ill let you know. The one in your link doesn't have a flange on it, how do you secure it to the box?I have 3 of the precision port 3" kits brand new just collecting dust, if you can't find them i'm sure I can part with one or two. As far as using a jig saw, just draw the circle and when you're cutting it out just stay inside the lines. It doesn't have to be perfect as long as it's pretty close to the line. The flare will cover most of the imperfections!