I installed a rear belly pan on my insight. Got some election signs recently so I have been having fun fabbing up some insight stuff lately. This was pretty easy to do.
1. 36x46 piece of coroplast.
2. Razor Blade.
3. zip ties. I used some heavy duties and some regular.
4.jack and jack stands. (just to jack up the back of the car.).
I just cut the piece and placed it under the car, it slips nicely between the bumper plastics and the bracket/wind deflector that holds the gas tank. after that made some basic cuts to the coroplast so it would fit better around the springs and exhaust pipe. Then I pretty much just zip tied it all up, I used the gas tank bracket and the coil springs and the muffler hangers for the zip tie attaching. Lowered the car, recheck all my clearances to make sure it wasn't touching the muffler or tires and that's it. Its been about a week now with temps up to 108* ambient and no burning at all! I left about an inch between the coroplast and the bumper and its never even hot to the touch. I haven't calculated the MPG gain from it but I can say that with this, my new Grill block and warmer temps I am on track to have my best tank ever. YMMV. I can ad more pics if needed.