tire foam makes it shiny but dang it makes parts greasy and a PITA to work with.
If you want someone else to do it check with detail shops most steam clean the engine bay with a detail job, or at least the good ones do.
I use a combo approach, Castrol super clean for real dirty engine bays, then rinse then simple green, rinse. Do mine at least every other wash. Gotta keep the bay clean spend too much time under the hood for a dirty bay.
I use Gunk spray on engine decreaser in a can for really tough stuff. Haven't needed it yet on my '04, but it did wonders on my old foxbody. Simple green works just as well if not better.. I just happen to have like 3 extra cans of Gunk in my closet.
I use CD2 detailer to make it all shiny and wet looking.. stays that way for a month or more usually.
Lastly, I use a steam cleaner I bought from Walmart's website (a Eureka something or other, big yellow one) to clean the wiring harnesses, nooks & crannies, etc.
Here is a recent pic of mine post Steeda STB install. I also use easy green and rinse off with hose, but only on light mist so I can control where the water goes. I follow up with interior cleaner/protectant, but not that real shiny stuff. I personally prefer the "satin" look. As all have said previously, placing a plastic bag over the altenator and coil packs if you have them, just in case.
I hate those shallow fins on the cam covers (valve covers). PITA to get in there.