Yah, I found the same thing with the Supra in GT3, since it was one of my favourite cars in real life a few years back after just about every car mag said it was the best car under $200,000 and they all unanimously agreed. And the first car tested by Car and Driver to sustain 1G on the skidpad etc etc.
Then I found out people were modding it to 1,400hp. (some guy in Saudi Arabia has a Street Driven 1,775hp Supra, I unfortunately havent been able to find the site for a year or two) This is back in like 1995, BTW.
It was my favourite car for a good 4-5 years, and then I moved on, but I still love them and I thought it would be able to handle a bit more HP.
I have a 566hp one in GT3 and it really has trouble staying in a straight line, even with Super Softs, It just has WAY too much low end instantaneous torque.