what kind of car do you have? the only car ive heard being VERY hard to clean are the B6 & B7 S4s. The coilpacks are easily destroyed.

This is how I clean engines:
Light spray with pressure washer
Spray down with p21s TAW
Agitate with various brushes: Mini EZ Detailing Brush etc.
Then rinse again with the pressure washer
Blow dry with leaf blower and use cheap MF to dry everything else
Dress with your favorite plastic/rubber dressing. I like to use 303 CG VRP, or Back 2 Black. Einszett plastic/vinyl is also on my list. Just depends on my mood i guess ha