I think these are high prices as well.

I would want an 80% var speed 2 stage furnace with a high eff AC for Texas. Of course properly sized. Preferably a system that also qualifies for Fed Tax Credit.

I would like to see all model numbers for condenser, evap coil, furnace, thermostat. I would not accept a quote without these. Also an idea about scope of work to be performed.

Look at Carrier/Bryant and Trane's sister company AmStandard.

IMO

Look at SA specialities they have specials going on right now. I believe they are in Houston too as I am in Dallas and just got a good deal on 3 ton 2 stage XR17 system. it is almost half of what you were quoted

I live in S Florida and currently have an 18yr old Trane XE1100. It's about to give out. Just received a quote to replace both handler and compressor. Needing a 5 ton.
I have a quote for 5ton XB14 and a TAM7A048H41SA. Is this a good matched set?
I searched and the TAM7 model above only says its 4 ton. I assume the TAM7A0C60H51SA for 5 ton will blow more volume of air?
Also this TAM7, I understand is like a refigerator with inner walls and no exposed insulation. Any thoughts on longevity and reliability?

Here is a link that might be useful: Example of Air Handlers