I know this was most likely discussed already, but, for a 300-400hp car...that will see some track time and some street time. What would be the ultimate suspension package?

 

in order: subframe connectors, Lower control arms, lower control arm relocation brackets, torque arm.

 

By track time you mean Drag or roadrace? I agree with the order of things and depending on your tires and rwhp numbers this can be over kill but look at BMR x-treme. And even thought a 4link is better you can go 8.90et on a stock f-body style setup.