I shipped UPS. Perhaps I should've tried another carrier. I did check the tubes.
Shipping was about $45. Materials, including a box, were $15.
UPS is always more expensive than FedEx, even if you have a UPS account.
And it was not as smooth as I imagined. Do they have to break-in or something?
Graphite's incredibly bad for the lungs. I wouldn't put it in a place where it's going to be under friction and put that stuff in the air. I used to work in carbon composites.
For low frequencies, you need bass traps. There are plenty of tutorials out there on how to make them from the DIY studio and A/V & Home Theater world. Do a google search on DIY bass traps.