I purchased a 2001 IS300 in mid-May. I asked about the ECU/TRAC problem then, and was told "This car is fine." Within 2 days I experienced all the early and aggressive TRAC behavior, and the potentially dangerous lack of throttle response (sometimes called throttle lag) described in this forum. I spoke with service at the dealer, and was told to use the power mode. That made no difference in the car's behavior. On some days, the problem was so severe I simply drove the car home and used one of my other vehicles. Now, the car has been at the dealer's for service for two full weeks, and I am told that it will be at least another six weeks before the TRAC update arrives. I have told the dealership I will not drive the car until it is right (I chose the IS300 over a BMW 330), and I expect Lexus to be taken seriously when they describe themselves as in the "relentless pursuit of perfection." I told the salesman I would sell the car back to Lexus before I waited another six weeks for the part, and was told the dealership would not buy a car back, AND if I wanted to trade for a 2002 IS300 I would be offered a discounted price for my car since it was known to have an ECU/TRAC problem. Relentless pursuit of perfection, indeed.