I have a bid for a new Lennox 5-ton system consisting of a HS26-060 (13.30 SEER)+ C33-50/60 coil w/TVX valve + G6OUHV60C-090X Lennox Signature two-stage furnace + a Silver Cloud mid-efficiency air filter. I'm paying $6,670 installed and hooked up to existing copper lines and vents. Is this the best equipment set-up for the price? Am I getting my money's worth? Is the Silver Cloud filter necessary? Please advise ASAP as I'm needing to replace soon.