I replaced my HVAC about 5-6 years ago, the old one was 17 years old and starting to nickle and dime us. Got a Trane, cost about $10k back then, had to redo the plenum to correct an air distribution issue that house has since we moved in. So your costs, including your upgrades, isn't too out of line. One real nice thing is that my summer AC bills dropped about 75%, from ~$400 a month to ~$100.