I'm not quite sure if you are asking about a drop in coil, or about switching to a 1.5 build, (sorry, this is not gear I know well) but there should be no problem using a 1.5 coil as long as your
mod fires low enough to support it (which it should). What wattage are you targeting? Usually, a higher resistance coil will be fine on a more powerful
mod, as long as you prime well and work your way up to what may be a lower wattage range, which should just give you more battery life. It's generally not an issue.
Anna