I notice that you sell a more powerful heater motor/fan to upgrade old heaters. Does this brand new system include a more powerful or efficient motor/fan? Or is it just a brand new (original spec) box?

The new system comes with the standard motor and squirrel cage. We can upgrade you to the heat blaster for an upcharge. You will still need to modify the hole in the heater box for the larger squirrel cage to fit.