I'm interested in how many sq ft of home you have and why the old unit failed? Have you considered just repairing the old one and going closed loop for about 2500

The home has about 4000 sq ft for first floor and the basement. No one can tell me why the compressors just died other than it happens with this kind of duel compressor design. All four contractors also gave me the quote for repairing the unit by getting a new compressor. The price is around $4000 with only 5 year of warranty. Since the warranty is so short, I might as well spend a little more to get the 10 year warranty especially now you can get 30% tax credit.

I don't think I'd be too interested in repairing any appliance with such a major problem reoccuring.
J