Is it possible to upgrade a furnaces BTU output and blower if needed? I am putting on a 2nd story addition- and yes I am having a energy analysis done-and was thinking of putting in zone with my 2 yr old furnace.

I would like to reuse my existing American Standard 80- 2 stage furnace. Can you upgrade this model's btu output and blower if needed?

Thanks
g-smitty