Best set up for first gen Mustangs?

[skooli]

So I'm almost finished getting my wife's Camaro back on the road and this summer I finally get to focus on my Mustang. I'd like to start with the chassis. I was wondering if anyone could provide me some insight. I plan on trying to do some road course stuff with it. Quick background info on the Stang:
It's a 68 Fastback with a pretty stout 351w and a TKO. The engine is good to go for the most part. The suspension is factory style with 620 coil springs up front. I think the sway bar is an inch and a quarter, and it has KYB gas shocks. In the back it has 5 leaf mid-eye leaf springs and Shelby style traction bars. It's tied together with welded in subframe connectors. I have factory style disc brakes up front and drums in the rear. The plan is to go with some sort of big brake kit from someone like Wilwood.
So here's my question, do I keep the factory style suspension and stiffen it up a bit? Or do I go with something a little more modern? If I go with an Air Ride or TCP system will I see a giant difference as a novice driver? I'm hoping to hear from some Mustang owners with at least some entry level pro-touring experience. Thanks in advance.