Get a Goodman! 10 years and with Labor 10 years. And for get the zone business. Install two smaller systems. Keep it simple, save money. Just find a NATE Contractor. Good Luck. If Carrier and Tempstar is made in the same factory...that doesnt mean anything....to day All of them are using parts, and compressor, interchanging things...keeping OEM just enough to keep you thinking there are GREAT Differences in the product. Yes they have good, bad, and ugly in all brands. Get a 10/10 peace of mind and forget the fluff.

Who installs the system is more important than the brand on the condenser housing.

I don't understand how two independent systems can be cheaper than a single system with zoning. If this was true then systems with zoning would not exist.

I agree getting a 10 year parts and labor warranty is a good idea, but Goodman is not the only manufacturer who offers it.

Do a search on Goodman in this forum. It seems the rate of complaints on Goodman products seems higher than other brands. For some reason Goodman products also seem to be associated with bad installations.

Tempstar is indeed owned by Carrier/United Technologies, same factories. They the "entry level" aka builder models which look almost identical to the Carrier/Bryant builder units. Then they have the "mainline" which is a deluxe model, a bit fancier than comparable Carrier/Bryant units with a better warranty.

But yes, key is the best possible contractor and good contractors seem to be getting harder & harder to come by.

Thanks for the feedback everyone. It sounds like I would be fine with a higher end Tempstar, but unfortunately I don't have a lot of confidence in that particular HVAC contractor. Especially when he said that he's been doing this for 20 years and he's always had more problems with the damper systems compared to 2 separate systems. He also blew off my request for a Manual J when others are offering the Manual J and the Manual D/S calculations.