Run it and the track like it is and see how it performs.
New leaf springs are a good idea but may not be necessary if it hooks.Subframe connectors should be mandatory(especially if you plan on it going faster).
Get it to hook and stop safely(front discs a big plus)safely and then go faster.
ALl the motor needs is a good set of heads.Everything else seems tork well together.
Make one change at a time.Hard to tell if you are going forward if you do multiple changes.