[cstreit]

I'd go wider if possible. With 20' wide you'll be contrained if you put in a row of benches along the wall and cars side by side. Mine is 24x40 and I enter on the 24 side. Still gets narrow. I'd shoot for 26 x40 instead. Gives you plety of width, and two cars deep with room for equipment and tables.

I can shoot some pics of my shop if you want to see what I mean...