Contractor is recommending the Carrier coastal 3 ton heat pump w/ the FX4 air handler as the best and most reasonable option for my 1 level aprox 2500 sf home. he also carries Trane and says that he was a Trane believer until 2 yrs ago. he will sell me a Trane, but he recommends the Carrier unit for about $5400. It is the Comfort 13 HP w/ a SEER of 14.5. Is this a good unit and deal and should I also consider the extended warranty for another $1500. I was leaning toward Trane because my neighbor got one 2 yrs ago, but his contractor does not even carry Trane anymore, he went to Tempstar units now. Any advice would be helpful. Thanks