With a major overhaul scheduled for the 2001 model year, there were few changes to the final version of the Lexus GS 400 in 2000. Just one-year later the car's 4.0 liter V8 would be replaced by a 4.3 liter power plant and the GS 400 would become the GS 430.

Changes from the 1999 model year included the addition of a BrakeAssist system and child seat-anchor brackets. Crystal White and Millennium Silver Metallic replaced Diamond White Pearl and Alpine Silver Metallic as color choices.

Drivers had few complaints about the GS 400, or at least fewer complaints than they would have about the first few versions of the GS 430. "Handling and performance wise, it is one of the best in it's category in my opinion," said one reviewer after five years of ownership. "It will stay with or outperform a BMW 540 any day and cost a lot less to maintain."