I wouldn't use the old one for anything more than the tank. Is the new one oilless as well? They usually run high rpms and are really loud. I'd take you're 13 gallon tank, and mount it on the wall next to where you're going to mount your compressor, plumb it directly into the output line on the new compressor, and then plumb your shop lines into the 13 gallon tank. Don't forget to put a dryer on the line before the shop lines.