I got a new air condition unit quote, to replace both outside unit and inside coil, using Payne equipment, plus 300 duct work which I would like the contractor to do, for a total of $2790 tax

The equipment is Payne 3.5 Ton with 13 SEER.

How is this quote?

I have a heat exchange furnace connect to the coil which I replaced 2 years back. It is pretty new and running well, so it will not be changed this time. I think it is 14 SEER, is it going to work well with the 13 SEER air condition? If I change the equipment to be 15 or 16 SEER, is it OK?

This quote is the lower of the two I got.

The price does not seem high but I would never consider a project like this without 3 competitive bids from local HVAC companies