Bro, the contractor can always build a rack to hse yr new compressor above the existing one if needs be. For the installation of compressor, all aircon installation contractor can do it but the problem is whether they know where to get ti or coated copper coil and install ext. Thermostat with controller and interface with the compressor. Lastly, they want to take on this job as they scare of loose end works. Cheers.