One problem related to manifold/header/muffler/tail pipe has been reported for the 1999 Saturn SL1. The most recently reported issues are listed below.
Oil was leaking from the engine going under the intake manifold. Consumer contacted the manufacturer to resolve this issue. However, manufacturer was only willing to pay $200. 00 toward the cost of repairing the vehicle. Consumer was afraid that the defect may cause the vehicle to develop a blown head gasket. . . . . . Vehicle experienced vibration in steering wheel when driving 50 mph due to defective brake rotors. Also, replaced engine head gasket.