What size were you quoted?
Carrier Furnace Model: 58GS125-4B Serial: 3091A01858
Carrier Air Conditioner # 38TKB042300 Serial: 119E31004
New Proposed Unit
Goodman Furnace Model: GMH8
Goodman Air Conditioner Model GSX13
Ultra Violet Air Sterilizer
What kind of house is it heating?
Based on the old model numbers, the furnace appears to be 125k BTUs and the a/c is 3.5 tons.
If I'm correct, chances are that the furnace is grossly oversized (70k 95% eff or 80k 80% is what you would typically see in a house of your size) and the a/c is on the large side unless there's no attic insulation or a lot of window surface area.
You were quoted low end equipment.
In Canada mid efficiency furnaces aren't even available any more - they're essentially obsolete.
General public's attitude towards our energy predicament: "I reject the reality of finite resource depletion and substitute it with my own; energy is infinite, we just need an alternative storage medium to run the cars on. The economy can grow indefinitely - we just need to "green" everything! Technology is energy! Peak what?"