Definitely a V-6 anything. We have a ford E-150 with a V-8 and the gas is ridiculous. With that said, the van is loaded with chemicals, tools, etc..... but I do believe if we had a V-6 it would get a few better miles per gallon which is significant in a mobile detailing set up. We also have a dodge 1500 that gets pretty rough MPG. At the end of this year, if possible, we will drop down to much more fuel efficient vehicles! So IMO, any cargo van can be made to satisfy your tools and products, but fuel efficiency is key in a mobile set-up.