I am getting a new heating and cooling system for my 4000 sqft ranch style home. My question is if there is a big difference between getting a 5 ton XL18i Trane Heat pump with a 120,000 Btu XV95 gas furnace dual fuel system and a 5 ton XV20i Trane Heat pump with a 120,000 Btu XC95m gas furnace dual fuel system. There is a $2000 difference in the final turn key price and I just don't know if its worth it or not? I plan on doing both systems with the XL950 Comfort-Link Thermostat.