I cut the hood on the vehicle. I used welding blankets to cover the engine and windshield. The sparks from the cutting wheel will etch your windshield. I propped the hood up with 4x4s so I wouldn't cut anything in the engine compartment. I used the template that came with the hood vent. Take your time, follow the directions. I live in AZ and when I'm at a stop light I can see the heat(distortion)coming out of the hood. It's why I bought it.