This is the system I recently had installed at my house. I don't take credit for any of the work, but they did a nice job. 4 ton communicating heat pump (XL20i) with matching air handler (TAM8). Also added a bypass humidifier and Honeywell media filter. Total static on high stage (1600 CFM) was around .55" with clean MERV 10 filter (.15 on low - 800 CFM). New properly sized lineset (3/4" x 3/8" is what Trane specs for 4 and 5 ton XL20i heat pumps) was installed. Proper procedure was followed: nitrogen flow, micron gauge, etc. System stabilized using the ChargeAssist feature. New disconnect with a surge protector. New properly sized flex return was added to the basement -- existing was tapped on one of the return trunks (feeding upper level) and was pulling a lot of air (making the basement very negative and never comfortable). We were prepared to balance the system at the end, but per the load calc the system was already well balanced with each room getting the CFM it needed. This replaced an 8 year old R-22 3.5 ton Payne 10 SEER heat pump "mis-matched" to a Lennox air handler. The heat pump had been problematic in the past and ultimately developed a leak. Decided it was time to upgrade to a better functioning, matched system. Hard to get good pictures of the air handler -- small utility space.