Well I have both models unlocked, and sync speed difference up and down doesn't change by more than a meg tops (my line is also crap as it's 3/4 copper and 1/4 fibre) (I would screenshot but I don't disconnect my modem for anything EVER. I have nightmares about DLM). A little Google on the topic confirms this for countless others both on Sky's hardware and BT's. Not arguing exactly (I am though) but was just saying, in the interests of giving OP the full range of opinion. Also an unlocked Huawei is much much cheaper to achieve than unlocked ECI and money seems to be a factor here as he could get a 50 quid router from argos stick ddwrt on it and a 10 quid Huawei off ebay and flash it himself= job done for about 60 quid with not the fastest wifi but at least decent n and gigabit ports.

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Oh bugger I should have used the "I'd love to agree with you but then we'd both be wrong" line...