FWIW The C1 and MKII had a 5 yr warranty where the Signatures had a 10 yr warranty. Not sure about the Platinums. I would also say the Dyn stands should be used. The Stand2/4 posts screwed directly into the bottom of the speaker (top plate wasn't used). So if a previous owner had either stand2 or 4 you will see rings on the bottom of the speaker where the post touches the bottom. The Stand6 has an adapter plate the speaker mounts to.
Again the difference in sound quality between the original C1 and the MKII/Sig/platinum is very hard to hear tonally it's with the later versions sound better at lower listening levels.
Again the difference in sound quality between the original C1 and the MKII/Sig/platinum is very hard to hear tonally it's with the later versions sound better at lower listening levels.