I do a lot of truck fleets and a good bit of oilfield work as well and have been running four machines. Three of them are gas powered and one is diesel. We changed the unloader to a large volume unloader and split the discharge hose into two where we can run two guns on each machine. To do this, if you have a 5 gpm machine which requires a 5.0 tip, you have to put a 2.5 tip in each gun to get the pressure back right. Doing this cuts your gpm in half on each gun, but works fairly decent with two stepping if you know what you're doing. Now, if all you're doing is rinsing, I don't know why this wouldn't work great for you. The gas ones don't hold pressure as good but you can barely feel the second gun kick in on the diesel machine. The diesel is an aaladin powered by an 18hp liquid cooled kubota with a 6 gpm pump. We needed another machine for oilfield work, and about a month ago I purchased a monster 10 gpm 3000 psi unit from aaladin. The model number is 46-1030D. It has a 33hp IZUZU liquid cooled diesel, two clutch-driven pumps, two burner systems, and is completely enclosed in a powdercoated cabinet. First one I've bought with clutch-driven pumps and I know now I will never buy another pw without clutch driven pumps. You can change guns without turning the machine off by just hitting a switch because the pumps are electronically controlled. Not only that, we have 60 hours on it and have not replaced the first o-ring and we have quick connects on the burners, the downstreamers, the guns, and on the tips and haven't had the first one leak. Now if you just need a pressure washer to rinse and apply soap, I would just change the unloader and add a second gun. You don't want to invest a lot of money into something you haven't got your first check from yet. They might get pissed about the smallest thing after the first wash and not let you come back. Changing the unloader and adding another hose, hose reel, and gun shouldn't be more than $500, $200-250 if you don't buy the reel.