The mod usually takes me about 4 to 4.5 hours. But you need to be pretty anal about how you cut those holes so they correspond to the holes perfectly in the rear of the driver. I also highly recommend taking a small screwdriver and using the flat surface of the blade to compact the Dynamat down nice and tight, You really need to work at it again and again, spreading it like very very stubborn frozen butter so it adheres fully and completely without any air pockets. This gets to be a major pain in the behind when working the rubber around the air holes. A pain, but well worth the result.