One problem related to manifold/header/muffler/tail pipe has been reported for the 1999 Lexus LX. The most recently reported issues are listed below.
Fuel return line rusted out under brake fluid tank. Danger spraying of the fuel right on the exhaust manifold and catching the fire. Tried to order fuel line for repair . Was told by dealer it is on back order and they have other 8 orders for the same part.