A squeak type noise may be noted from one or both front seats. Squeaks can be caused by contact between the seat track locating pins and the vehicle floor pan. Our technicians tell us the repair involves removing some of the seat locating pins.Google+
Car Problem Reports
Lexus SC430 Squeak Type Noise from One of Both Front Seats
Lexus SC430 Problem
Visitor, 2004 Lexus SC430
Do you drive with one or both seats fully back or with the backs of the seats inclined backwards so that in either case the seatback(s) contact the bolster(s) of the rear seats? Makes an 'orrible scratchy/squeaky noise,
I suffered it for ages before I twigged.
If that's the answer and you don;t want to move the seats forward or adjust the rake, suggest draping, say, a soft yellow duster over the front of each rear seat. That will get rid of the noise and polish the leather at the same time!