Yeah testing after each change would have been cool to know what made what difference.
Yes for sure that would have been a better method. But I was going to do all that stuff anyway because it was cheap and I had done it before on other cars so I was just taking a shotgun approach to killing every possible source of noise I could think of. There was probably more work than a scientific approach but it was effective because the car is now significantly quieter on the highway. Others have done scientific testing on some of what I did but I don't believe anybody has done a scientific measurement of Dynamatting of the doors or the trunk area. But there are measurements on the door seals and the neoprene tubing around the glass. Don't have those Links at my fingertips but I know there's threads on both of those two on this forum.