Two theories.
1. Your boom is not coming from the hatch. My vehicle was missing standard insulation. Adding it helped a lot, more than anything I've done to the hatch so far. But I still get plenty of boom on textured pavement. I will be trying the tube insertion and rigid hatch stops over the next few days. If I still have boom on textured pavement then I will be in the same boat as you with my hatch.
2. You are driving over a type of textured pavement that others (except maybe me) here have not encountered. Unlikely, yes, but I want to put it out there because you could fool me into thinking I have a quiet car for quite a while now if you know which roads to avoid. Roads in my neighborhood for example are fine. But then I head out to some groovy textured pavement and the boom is amazing.
- I actually bought the $130 Amazon special of insulation you had success with before I read about the rigid stops and tubing. I thought those would be easier, quicker fixes, so I tried them first. Butyl and foam are for next weekend.
- Most roads in my area are fine. The road in my neighborhood and the "boulevard" to my kids' school is asphalt that has been "repaired" with stripes of oil every year. I drive these roads every day and they are "tha-bump", "tha-bump", "tha-bump" that I interpret as the booming. The road I take to work was repaved last year (asphalt) and they are fine.
I did the 5/16" tube first. The hatch would not close on it's own. I forced it to close and the gap was huge. Upon reopening the hatch popped so loud I dared not close again. I removed the tube. I then bought 1/4" and 3/16". I figured the 3/16" would be easy to install, so I tried that first. The gap was better, but it still popped upon opening so I knew there was rigid seal contact. Driving still had the booming. Then I made the rigid stops, sanding off a millimeter at a time until it fit perfectly. Everything is screwed in tightly - rubber stop and plastic nut. Then on the road to school, I thought the booming was louder than ever. I may have just been frustrated and had my sensors on high though. The rigid stops are off for now. I'll try the felt pads soon.After inserting tube, I actually backed off the rigid stops a little so that the hatch rests on the gasket and not on the stops. If the catch holds the hatch so tight that it pops when opening, it unlikely that the hatch is moving anymore. As Pecunia mentioned, the problem is probably lack of insulation.
Of course there may just be a glitch in the matrix or I am crazy (or getting there ).
Thanks for the comments everyone.