We have the experience that Fr drive make the compressorpack more flexible. You recieve more flexible cooling capacity on a m2 . and that means investment in 1 time - if you need later more capacity your compressor packs are prepared on it. however you need design teh pack on this. only than this can be a succes. regardless the used compressor. we buils and re-build new and used compressors sets with fr driven. and we give two years warranty. of cours it can be tricky- basic you create a onter variable in the amount delivered to the suction of teh compressor. but after making 7 years mistakes , we can final we have a workable product. Bur guys it true we had sometimes pain in the stomage. But we learned a lot. blistering, lack on lubrication, hammering- bended rotors. basic I would not miss it. I helps me each dayby my job.