Safety REQUIRES a roll bar or cage in conjunction with a race seat / 5 or 6 points. And they should never be on sliders.
Its very difficult to make a street car into a track (dual purpose car). Something always comes up short. If you go too far on the track side, its a miserable street ride. Before you mod your 987, consider buying a dedicated track car. I've done it both ways, and have learned that having the dedicated track car is the way to go. A 944 all prepped for the track can be had for under $ 5k, for example. Like this one:
Porsche Track Car - Awesome 944