i've been a detailing "geek" since the 60's and have always washed and waxed the paint in my engine bay. what i've learned over the years is the importance of first making sure that the paint is clean, which is often easier said than done, depending on what the previous owner(s) left you with. back in the 60's and 70's when i lived in the new england area, i always used a steam cleaner to clean my engine bays, followed by hand waxing. now, imho, nothing comes even remotely close to cleaning a dirty engine and engine bay like a steam cleaner, and with a little practice you can get by without having to protect electronics with protective plastic wrap. so, if you have access to a steam cleaner, i wholeheartedly recommend your using it, as it will save you an enormous amount of time, and clean places you'll NEVER get to by hand. then, wax away. you'll be astonished by the results! just make sure that you have a means of controlling the greasy runoff, ok.

as noted by others in this thread, the crossfire engine bay is not clearcoated like the car's exterior, which means that you are not going to get that deep shine that you want in the engine bay like you have on the exterior paint, which is a real bummer, imho... but don't let that stop you from waxing the engine bay, as the result is still well worth it. enjoy!