Hi Everyone,
I was on here before asking about my broken electric furnace and whether the tech diagnosed the issue correctly. Well the thing broke again and he tells me I need a new furnace and I'll need to pay $3,250 to build a stand for it (it's currently hanging on the wall) reroute the condensation line and vent exhaust, and to add a new subpanel to my circuit breaker since the new furnace needs two breakers and my panel is full. Note that this doesn't even include the cost of the new furnace.

I thought this was fishy so I had two more people give estimates. One says he can put in a new furnace for $2,000 with a new stand, and that I don't need a new circuit breaker panel. The other says I can just replace the air handler for far less money and that I don't need a stand.

Three people, three answers. I know that none of you has seen the furnace so you can't really tell me which guy is right but could you answer these questions?
Do I need a new circuit breaker if I get a new furnace?
If just the air handler is broken, should I just replace the air handler and not the entire furnace? I know that newly installed AC units need to be 13 SEERs, and I was told that 13 SEERs don't work with old furnaces so if the AC unit ever went out I'd need to replace the furnace too.
If I do get a new furnace, what's a good recommendation? Can you just go by the square footage of the building? (My place is 1,000 sq. ft. 500 each on two floors).