I was more concerned with air storage when I built my setup. Tom I think you looked over my shop. I have yet to spray or d/a an entire car. But I have been using alot of air. I have room for expansion if needed. And I have yet to run low on air with a one man shop.
If i were you (as I did) I would monitor craigslist on a daily basis. And jump onthe first deal I ran across (as I did). Found a guy that had a good speedair in the exact size I wanted for less than I wanted to spend. It took about 2 weeks to get exactly what i was after.
The key is don't hesitate!!! If it's on there, contact them
Immediately. The good stuff goes fast. Sometimes within minutes of listing. Ask me how I know.