If you keep the tip well away from the paint and also use it at an angle (not straight on) it should push most big stuff off, without doing any damage. Not for engine bays for me, unless you know exactly what electrics you're covering up and have some brave pants.
I've got a K2, it's ace. I use it on the Zed mostly, but also on the patio (without attachment, just blasting away with the jet) does a great job, even done the windows with it. Only negatives for me, the supplied hose (from unit to lance) is a bit short, so I bought an extension. The karcher foam thing was rubbs, unless it's thrown in for free, get a proper one from polished bliss or similar for snow foaming.
Quite tempted to try the underbody attachment and see if it will a) go underneath my sidesteps and 2) help keep corrosion at bay.