I use eGo Mega Dual Coils (1.7Ohm) with eGo Twist for months. Never had a problem, just don't set voltage too high. I personally prefer 3.8V. Of course, any 2.5-3V would be OK with Twists, as you always can set proper voltage for them. The difference between single and dual coils is that dual coils are in fact two coils working in parallel. So 1.7Ohm dual coil is in fact two 3.4ohm coils in parallel, so producing (in theory) twice more vapor than single 3.4Ohm.