I do still use the pressure washer on modern cars...but my intentions aren't exactly the same. I do not attempt to wash the engine itself - it doesn't bother me if it's dirty - but I do, however, pressure wash the strut towers, inner wheel wells, the rad cradle, battery tray, other sheetmetal nooks and crannies, and steel cooling lines where salt buildup over the winter may cause corrosion trouble down the road (I'm not worried about it looking clean, just not corroding). Grease, oil, and regular dirt is of little concern and can stay in place. Most of this stuff you'd never be able to reach with solvent, a brush, and eternal patience without disassembly (take the rad out of a daily driven northern vehicle, and be amazed at the years salt and corrosion you may find underneath!). Much of it really needs to be rinsed clean to be effective rather than wiped off. Again, this is done carefully as to not directly spray the engine itself. I do this once every spring when winter's over, and have yet to experience any negative results...
