At any rate, American Standard is a decent unit, and ranks high in Consumer Reports. If you have to pick one, that is where I'd go.
Honeywell on the other hand, I have not seen one in years... Current manufactures off the top of my head include Carrier, Amana, Rheem, Rhuud, Lennox, York, Goodman, Heil, Trane, Westinghouse, Weatherking, Bryant, Coleman - I'm sure I'm missing a few...
I don't believe Honeywell makes a a furnace anymore - they do lots of controls though... Flame sensors, gas valves, contactors, humidifiers, limit switches etc...
The upgrade is part #1213. It was installed for me but I think the cost was about $80.00 for the conversion. Well worth it in my opinion. If you're mechanically inclined, I bet you can do it yourself.
The new filter for the upgrade is #213. They are about $45.00, but they last one year. Just slide out the old, slide in the new.
You can see by the picture it comes in a small box. Just open the box and the filter expands like an accordion. The just slide it on the tracks. No combs, nothing to break, done.