I hear you. You should take some time to really research the matter. It's an important, and frequently forgotten, issue. A fire is pretty close to the bottom of the list of hazard, with running into something pretty close to the top. The fire I mentioned before is the amateur event where the drivers fire retardant gear came into play; it's worth noting that he wasn't a guy in a HPDE 1 car, he was driving a Mazda/MER car in a major endurance race.
Do some research on the SCCA's site, ApexSpeed.com - The faster you go, the more you need.
, SportsRacer Technology Forums
, and probably many others. Safety is a real concern for real amateur road racers, and a matter largely forgotten about in the street/track car world. Decide what risks you will take, and exactly what you want to do.
I decided that playing around on track can wait until I have an appropriately equipped car that will be used exclusively for the track, and go out in full gear. Many people don't agree with my assessment of the situation, but it's what makes me comfortable.
All that's important is that you do what makes you feel the most comfortable, and complies with the sanctioning bodies requirements.