Using a pressure washer would contribute to loss of grease, pressure from a hose is minimal and shouldn't be a problem. Ultimately not spraying directly at key areas is what you'll want to avoid same goes for just about any other thing you're washing where vital components are located.
Investing in different hose attachements will be wise as depending on the attachment design you'll get different spread and pressure of water, nothing significant but its bound to help get some dirt off.
I watch your videos on YouTube all the time they are some of the best videos I watch ..do you think you can do a video of an oil change sometime. ?.... thank you keep up the good work with the videos love them.....is your youtube name..... Polhamer?