got a few "looking good under da hood" mods. had the valve cover powdercoated red. then got a chrome heat sheild to rid myself of the crappy stock one, and still keep the heat from melting fan shrouds and casings.
i asked the guy who owned the car that i saw that heatsheild on first and he said it hasnt changed colors yet, and he was running a 60 trim. i had the same thought too but if it gets that blueish tint than thats ok by me, just means its doing its job.