I painted the fuse box, header heat shield, and abs fuse box. I also painted the plug wires once which completely messed my car up. DO NOT paint the plug wires. but hey i learned from my mistake. As for the hoses, i think the things that go around the hoses look best taht you can buy for real cheap.
you can't paint anything under the hood as long as you take the right type of prepping into consideration. Also the right type of paint. Think about how hot it really gets under the hood and where the hot spots are. But i would go all high temp paint just in case. There are all types of colors so good luck.