Most will agree (or not!) that ARC is known for quality pre-amps. I would not be shy about buying a used one, but check the reviews. Some are "better" than others for certain types of systems. They started in the 1970's with the SP-3, and even those go for HUGE dollars still today. Newer ones are improved. I personally use an SP-6B with Maggies and it is amazingly good. BUT, it has to sound good to YOU in YOUR ROOM. Happy shopping!
Cheers.