Beginning in 1998, Lexus introduced side airbags as optional equipment. Lexus does NOT recommend replacement of original seat covers with non-Lexus leather or other seat cover materials on vehicles due to the following: Seat covers NOT recommended by Lexus may affect side airbag performance, in general or in part, during an accident. Modifications that negatively affect side airbag performance can result in severe occupant injuries. Seat covers are an integral part of this safety system. Replacing fabric seat covers with non-Lexus leather or other seat cover materials may compromise the effectiveness of this safety system. The design of the seat is complex, integrating safety and strength with comfort and luxury. Lexus strongly discourages modifying original equipment seats that have optional side airbags. Additionally, Lexus strongly advises against the installation or use of aftermarket seat covers, which could impair the performance of the side airbags in the event of an accident.