When I bought my 2300 psi gas powered I thought I might be able to clean my CRV with it. Not so possible, dirt seems to come off your house and driveway with less pressure than it takes to get dirt (or bugs) off your vehicle (this is with water only-a brush attachment would not be a good idea either unless you want to scratch your finish with dirt). I pressure clean the roof, house, lanai, pool, driveway, etc. However, it is too much hassle to use on the vehicle and does not work as good as a bucket and mitt/sponge.
I don't believe my 2300 will take the paint off although as I said, you would almost need to remove the paint to get the dirt off.
If you buy a gas, it is worth paying for a good one that accepts universal hoses, tips, guns, extensions, etc.
If you buy electric, a pretty good brand is "Karcher" that is sold at Lowes Home Improvement.