hmm.....didnt realize that the entire engine bay basically was covered in gold thought it was just the cats (they are covered). found this little bit on it.

The heat generated by its large engine and its catalytic exaust system is a problem, the heat-isolating material is extensivly used to protect the cockpit and various ancillaries. The efficiency of the insolating material has been increased by facing it with heat-reflective marerial, the most efficient of which is gold. This is quite extensively used, mainly in the engine compartment, at a cost of approximately $3500.