Hello all - hope everyone is doing well. Looking for a sending unit to control the cooling fans on my big block Dart. I've read that it's best to go with a 2 wire unit if it's going to be mounted in aluminum ( aluminum heads, radiator & water pump housing). I've also seen external sensors (Derale I think) so I'm not sure which is best. Anyone have any "real world" advice as to which style or brand to go with? Thinking about running the Ron Francis dual relay setup because it's neat and somewhat compact. Any help to steer me into the right direction and avoid a headache or two would be appreciated. Thank you in advance. <><