here are the answers from the seller GT-sound
http://www.gt-sound.com/
HI Ari Oskarsson
Is it alright for a while, how are you?
Did you finish the Speaker box?
TD-4003
① DC-7, 5 Ω is normal value.
AC measurement will result in 12 to 13 Ω.
② I checked the sound at the time of shipping, but there was no
abnormality.
We opened the back chamber of DRIVER UNIT of TAD, GTS, and diaphragm
I will not remove it.
1. It does not have jigs that make precise height adjustment when
setting again. I have a TAD service.
2. The material of the diaphragm is beryllium and it seems there is a
danger to the human body.
Best regards
K.Goto
I am 100% sure he did not opened the back cap