I have a 2003 es300 and I was also looking for performance ecu chips.
The only thing I could really find for 2003 (everything else ends at 2001) is one called a g-box. Has anyone ever heard of it and do you have any info on it such as reliability, true performance, etc. If this one isn't good do you know of any others for 2003?? Thanks
Also i was considering ordering a couple of spiralmax's from spiralmax.com
Anyone ever use these? What were your findings?
John