You've got a shop with a cnc mill and lathe and you want to upgrade your compressor. The newer Sanborns are more home use compressors. The main company (MAT) has better compressors in there Industrial air line up. I think you want a magnetic starter, 1750+or- rpm industrial grade motor, intercooler, probably 80 gal.
vertical (just assuming here). You can grab one for between $1500-2000 I would imagine. Look at the Northern tool and AirCompressorDirect site to get a feel for what's out there and what features are available. Ingersoll, Bel Aire, Quincy, Chicago pneumatic, Champion, Curtiss and on and on all have what you want. Once get a part # in your head then go online and get the best deal..... many have free shipping and that's on a 600+ lb. item. One outfit that is in the midwest and seems decent is CastAir in Minnesota, If you talk with the owner and explain your needs- he will tell you what to buy, even if it is from someone else. That happened to me. I have no affiliations with any of these people, just trying to hopefully point you in the right direction. There are many other options but I'm using the Menard prices and assuming you want to be somewhere close to that upper price range. Many good used compressors for sale but now your venturing into somewhat unknown territory. Good luck.