I have an RT-N16 used with DPC3825 bridged and torrent bandwidth (both up and down) maxes out almost every time. I'm on BB50. Even when I wasn't using it with a router (and just the DPC3825) I got 1-3MB/s download and maxing out upload. Are you using the modem/router combo?
WiFi and ethernet connections in my car, the RT-N16 is also 12 volt input, so I wouldn't need anything else to power it, just straight into my car's electrical... -- Yes, I am not employed and looking for IT work. Have passport, will travel.