Heat Pumps and Electric Heating - Replacing a 30 Yr Old Heat pump, etc

A newbie here.

I've inherited my "Mom's " house in Sun City AZ which was built in about 75. It's about time to replace the heat pump, (original) and I'm going to get some estimates in November, over Thanksgiving vacation. I'm currently looking at the Trane and American Standard 'dealers' for replacement units.

House is one story, about 2000 sq ft -on a slab. The Air handler is in the hall closet, with the return air coming through a lovered door, and overhead ducting basically a straight run the length of the house.

So -

Currently thinking I could use the XL15i - would this be sufficient for that area of the country?

Since heating isn't as much of a problem down there, but heat is required , would a 2 stage compressor be better for that area ( from what I've read here - it's less efficient in the heat generating department) ? Can I get the 2 stage compressor in this unit - versus the 16i "upgrade".

Since I "assume" that the air handler primarily is a blower, can they retro a new "blower unit" into the current 'box" without ripping that one out?

I am expecting to be able to use the current "plumbing" , that's probably buried in the slab, to handle the refrigerant back and forth. Am I in for a Shock with this expectation?

What would be a reasonable, ballpark, dollar amount I might be looking at - worst case scenario.

Thanks All for any input and recommendations.

( Edited for typo's - well after needed )

Get 3 bids for the job for sure. How long will you stay or own the home. Thats like will say what units to go with . So you get a pay back . Id go for the XL15i stay with R22 it will be here till 2030. You also need a new V/S blower. coil unit inside. Now that will give you a SEER of 15.10 and a HSPF of 8.05. Dont like the 2 stage compressor . They just have a unloader in them. The bigger unit with 2 compressor is very good. But cost just the 1 compressor 1 stage is best .
Also with the seer over 15 you can get a tax credit for $300 and with the V/S blower a $50 from the IRS.
Cost is just to hard to say Different all over .

ED ;)

Thanks Ed, I appreciate the input. - The plan is to retire there and be carried out, so any cost recovery is kinda irrelevant...

I noticed on another 'consumer" site that the American Standard was rated less favorably that the Trane - I was under the impression that they were both made by the American Standard. Do they "under build" the Am Standard.

Yes same company lot of parts are the same . But the Trane is heaver so there is more to them over the A/S.

ED;)

You mentioned that "You also need a new V/S blower. coil unit inside. "

Should they be able to install that in the existing housing? ( the - what I'll call Air Handler inside unit) ?

Thanks

Yes they should be able to put a new blower coil in side. You want the inside and outside unit to be new and match for the right SEER and HSPF

ED ;)