Am i being unfair or is this a recipe for big problems?

Two chillers on a site in London. They are made by COSFI, with COMER V5 semi compressor's. Shell & Tube type, remote condensor. They were made in 2001, so far they have lost two compressors, and no one seems to know why. I was asked for a price to replace the compressor, having found out the above, i felt a little reluctent to get involved as it looks like a can of worms. having spoken to the Italian manufacturer, they no longer make the V5 model (343m3/h), the best they offer are 320 m3/h & 407m3/h. i have serious doubts whether either option will fit the chassis of the chiller or even perform to any extent. Anyone had any experience of these or have any suggestions?