If you'r going to be using a small sand blasting cabinet, air sanders or painting your truck, look at units that provide 14+ cfm @ 90 psi minimum or your work speed will be compromised. I think 2 stage pumps recover faster than single stage. A true 5 hp motor will draw at least 23 amps @ 220 volts. An advertised 6.5 hp motor that draws 15 amps @ 220v is really a 3 hp. Opt for a cast iron pump rather than aluminum. 60 gallon air tank minimum. Vertical tank saves room. cost <>$1000