Actually looking back through it, I'm a little surprised at the Lexus, seems like all the articles talked like it was a bit of a dog, and I guess compared to the Cadillac's it is. But really, considering the prices for it and the Caddies, maybe I shouldn't be that wowed how they compared to the Mustange, they're twice the price.
And also back to the GT versus Mustang GT, I'd guess tire compound alone makes probably half the difference there. Couple that with all the new work on design and setup of suspension and handling would be the other major boost. The GT was a pretty simple machine when it comes down to it, just good old fashioned mix of power, weight, and layout (mid-engine with big meaty rear tires). It was more in line with the Vipers. And for the person lamenting how a Cadillac sedan can best 10 year old Viper, well its the same thing, and its why the new Viper has been such a relative disappointment, as just to compete you basically have to properly setup electronic aides and the tuning of the car. The Viper basically needs to go ludicrous, which is why the SRT version I think could very likely really wow people and in real racing would handle the Z06 Vette, as it has a lot of features that make it ludicrous for a street car, but great for a track car. But they either need to work on finessing the Viper into a modern dignified brute, or they need to go supercharged and get 800hp so that it becomes scary again.