I have the external td and it is no problem. Just have to watch the wire when launching, but I don't have mine installed the right way. Definately go with the Terrova. I did the same research you are doing 2 years ago and the Terrova was my choice. Never looked back at cable steer models. A lot of you guys talk about single polin being a problem for the Terrova, but I love it. Used my copilot and never touched the foot pedal. Now I think about it, I only use the speed adjuster on it while trollin. Haven't used the pedal for steering since copilot was installed. Just got my ipilot in last Friday, but haven't been able to get to the water to try it.