JFB, our Pantera doesn't use such a system but I competed in another Pantera for a decade that had a pro 5-lb, 3-nozzle Halon system from Pegasus Racing in WI. One nozzle pointed at the driver, one at the carb and one at the stock fuel tank. Halon or other 'freon' systems are still available and legal; I recently wrote an article for the POCA Newsletter on these.
Never needed fire suppression (thank goodness!) and the only problem was the large 2" dia actuating button; the owner chose to place it on a bracket just below the dash near to the ignition key. He was shorter than I so it worked well.... for him. But every single run I made, I somehow managed to pop the safety lockout pin out with my knee- it would be dangling when I came into the pits. Didn't happen with him or with my 5'2" wife.
This car also had Recaro seats which again fit him fine but raised my 6'2" head into the roof; I had to drive with head cocked sideways a little. The combination of seat position & worry about popping the safety pin and accidentally actuating the fire system made the experience more stressful than it needed to be.