Where in Texas? Humid? Desert? FOUR systems? Is this a rental property with 4 units or a 12,000 sq ft home?

Need more info.

I will assume you are sized correctly, yes a big deal.

I would stick with an 80% eff furnace with var speed blower.

So with Trane, your choices are XC80 communicating or XV80 non communicating furnace.

Start there and then decide on AC condenser.

XV18 communicating condenser or XL18i, XR17 non communicating condenser.

Then the appropriate Trane thermostat/controller and Trane air filter.

Obviously a very large high end custom built home.

IMO

skin77a Reply: In HUMID area of Texas. It is a large home. I believe it is sized correctly based on load analysis.
Comments please - thanks.

tigerdunes Reply: What do you mean "yes a big deal" ?
re there any advantages to the 18 seer units you mentioned over the xv20i other than price?
Thanks for your comments.

Correct sizing is a big deal.

Weigh the cost difference between the XV20i and XV18i.

Be aware that on some of the system configurations with the XC80 communication furnace and these var speed AC condensers, the cooling BTUs may be light for a 4 ton. Ask for the AHRI matching number for systems quoted to verify performance/efficiency numbers.

The XC80 with these communicating condensers will require Trane's top end proprietary thermostat/controller.

And of course you will need a Trane air filter box.

IMO