Lexus 2003 LS Owner's Manual page 176

COMFORT ADJUSTMENT
16L327
A If the driver's seat position does not allow sufficient
space for installation, install the child restraint
system on the rear right seat.
162
16L428
1 Fix both seats at the same position.
2 Fix both seatbacks at the same angle.
CAUTION
When installing a child restraint system in the rear
center position, adjust both seat cushions to the same
position and align both seatbacks at the same angle.
Otherwise, the child restraint system cannot be
securely restrained and this may cause death or serious
injuries in a collision.