Carlyle replacement compressors suck. They don't give you a new electrical box and some times you have to cut the old electrical box a little to make it fit, no gaskets for the oil pump if you have an electronic oil safety, no spare sight glass o-rings if you have to put on a oil level control, not to mention the unloader issues. You need to remember anything else "extra" and buy it or you find yourself scrounging old bits. Luckily, the old parts usually work out, but not always.
It is a good tough compressor all and all.