This fuel pump will support at least 550 rwhp.  That will be plenty for the Lexus V8 cars.  This pump would work best with an after market fuel pressure regulator like the Aeromotive FPR.  FPT006 Walbro 255 L/H High Pressure Pump.  This pump will work on the below models for $130.
90-98 Lexus LS400
FPT009 Walbro 255 L/H High Pressure Pump.  This pump will work on the below models for $130.'94-98 92-97 Lexus SC400.  Instruction on fuel pump installation.