I'm planning on building a home and have received a couple of HVAC bids. Based on the reading I've done here I've pretty much decided about the type of system I'm going to try to get. My system of choice, based on features and not brand, is for a 12 or 13 seer AC unit, preferably with a 2 speed fan. Furnace will be 80%, preferably 2 stage and 2 speed fan. DocHoliday on this site has offered his opinion that a 2 speed or variable speed furnace is more valuable in terms of comfort than a 2 speed AC in my climate (hot dry summers and mild winters rarely below 35-40). Doc, sorry if I've misquoted you!

One of the bids I received (before I narrowed down my preferred options)was from a Trane dealer and he bid me a 12 seer AC. From my reading here I understand that all brands have builder grade units and higher grade units.

I've looked at the Trane website and have listed below the features of the listed 12 and 13 seer units.

XB12 XR12 XL13I
Climatuff Compressor
Spine Fin Outdoor Coil
Corrosion Resistant
Weather Guard fasteners Not stated
Noncorrosive base pan
DuraTuff Rustproof
base pan
WeatherGuard II top
5 year limited
warranty on compressor
10 year limited
warranty on compressor
Single speed fan
2 speed fan

My guess is that my local dealer quoted me the XB12 unit (I'll call him Monday to confirm).

Here's my question: Are there any other important features not listed above that would be of interest to a professional member?

I notice that Trane states that all models have a "Climatuff" compressor but the XB12 has only a 5 year warranty. Is the Climatuff compressor the same across model lines or does the technology differ?

Thanks very much for your assistance.