Reply to "Race shocks"

I'm afraid you're going to have to guess and try. Ultimately, it depends on how rough the tracks are in your area, how heavy your complete front suspension assembly is, how high the chassis is set and a few other factors. If you're serious about this, you'll wind up with a boxful of springs because each track will need slightly different ones. Ideally you want the car to not quite touch down the front airdam or any other part under max braking or traversing an 'average' bump. Too soft and aero loads at high speed will push the chassis down further than you'd think possible while too stiff will cause the car to hop high over bumps- 'there's little traction with the tires in the air' (Carrol Smith- 1980).
The rear is less important but should stay balanced to the front. As an example, our lowered street Pantera has been severely lightened so I can run 250 lb front springs & 275 lb rears (plus I get 45 lbs more per corner from using Koni gas shocks who's high gas pressures add to the spring pressures), and not have our Revson front spoiler touch down on track or bumpy public roads. So it's a highly individual thing depending on the car involved.
AVCO non-plated springs from Speedway Motors for my Koni gas shocks are less than $50 each & install in 30 minutes. Street Panteras are typically sprung way too stiffly IMHO, and track-only Panteras need better damping than most street shocks provide, apart from the spring strength used. Good track shocks may have remote fluid chambers, will be priced around $1000/corner and have adjustable-everything. You'll need it, too. A set-up notebook will help keep you from getting lost in the adjustments.