Todd,
What is the anitsquat set at in the back?
Here is my mustang with a tri-4link set at around 125%. Less than 300hp but launching at 6200rpm with 10.5" slicks. I also have AFCO double adjustable shocks on all four corners, but lighter springs in front and rear than a typical pro-touring car. Typically a second gear burnout hitting the rev limiter at 6200.