It's VERY important that the engine is NOT hot. A warm engine will get you best results. Also, if you have some type of open air filter (CTA, KKM, etc.), you have to be real careful not to get anything in it.
This is what I did just a couple weeks ago: I wrapped my CTA up with a plastic grocery bag and sprayed a whole can of engine cleaner over the ENTIRE engine bay. After a few minutes, I took the bag off, and started the car up. I used a regular garden hose to rinse everything off making sure I stayed away from the air intake. After rinsing, I shut the car off, and took a brillo pad to the stubborn spots. Started it up again, and rinsed it good again. I let it dry real good, then took some armour all and sprayed everything but the intake down & polished with a soft cloth. May sound crazy, but it makes for a nice shine, and won't harm anything. Just don't be afraid...get in there and do it quickly but carefully, and everything will turn out fine.
Good luck...it's well worth the time.
*EDIT* just noticed you have a stock airbox. You should have nothing to worry about as long as your car is running when you rinse it.
