Just checked my 05 and the passenger seat goes right back even squashing the rear seat. Interestingly if it is reclined it auto reclines up as it almost hits the rear seat. There is a US bulletin on seat position if the battery is disconnected:
PG005-03 INITIALIZATION OF FRONT SEAT POSITION AND SEATBACK ANGLE (REVISED)
8/19/2005 - 2004, 2005, 2006 Lexus SC430. This bulletin explains the initialization procedure for the front seat position and the seatback angle on 2004 –2006 model year SC 430 vehicles.
To reduce parasitic current draw from the battery during transport and storage, the D/C CUT fuse (15A) has been removed at the assembly plant. As a result of the removal of the D/C CUT fuse, the following will be inoperative:
Automatic seat adjustment.
Driving position memory of the front seat.
It is necessary to initialize the front seat position and the seatback angle after the D/C CUT fuse has been installed during Pre–Delivery Service (PDS) or whenever the battery terminal has been disconnected and reconnected.
File is associated with other vehicles. Product General Information 2004 Lexus SC430 2006 Lexus SC430
08-19-2005
Cheers
Paul