Just bought a 516 and a 546 from dslsource.
The 546 was v5 and the 516 was upgraded to a 536v6 no charge.
Difference seems to be the version of the broadcom chipset but I noticed that the 516v6 seemed to synch OK at 6.5db SNR (only tested for a couple of hours while I was setting it up for a friend) but the 546 seems to resynch at below 7db due to the large numbers of errors (I have a long line so synch is at about 2,960)
Edited by deleted (Wed 07-Jun-06 12:51:07)