Hello, We just had a 3 ton Trane/American Standard Allegiance 13 with r22 installed for our second floor. We now need to replace the furnace/blower, coil and line set as per the AC guy as they are too small - there was a 1.5 ton unit previously..He quoted us 5K which I feel is steep. I found a furnace blower and coil on craigslist that is supposed to be new for $750..so how is this Ac fellow charging me 5K? Does anyone have experience with this? Thanks very much...