I'm considering either the Amana Air Command 95 II 2-stage furnace which I know has an ECM variable speed motor or the Rheem Classic 90+ 2-stage. The Rheem website is somewhat unclear whether their Classic 90+ 2 stage RGRK series has a variable speed motor. Reading the spec sheets it looks like the Rheem has a conventional blower motor than runs either at low or high speed depending on whether it's operating at low fire or high fire. Could someone confirm if this is correct?