I finally demanded that the Lexus dealer actually take a look at my heat shields since they keep saying that they are the source of all the pinging after the car is shut off. Well, lo and behold, my catalytic converters have gone bad and are starting to deteriorate which is the source of the noise. Lexus quoted each cat at $718. OUCH! Discount converters quoted $178 each for new OEM cat converters. (Hopefully the cashier isn't dyslexic!) Anyone ever use these guys?