If you decide to buy a modem from auction then get hg612 not the eci version
the hg612 is the one you are looking for and it only need unlocked if you want to see the stats otherwise it is plug and play
Further update. I have installed a HG6123b modem and the download speed is 67meg with a similar max achievable rate. I have noticed that the SNR margin has increased from 6dB to 14dB - Any ideas why this could be?