HPDE events are open as far as car mods go, it's all about being safe. You are classed by run group based on *your* driving experience, skill and behavior, not your cars performance potential or modification level.
Chin tech form is here, but it's really less stringent than many state inspections. I imagine NASA is similar.
https://chintrackdays.com/forms/techSheet.pdf
Now if you are talking about racing, that's something else entirely and you need to talk to NASA, SCCA, etc. about the class(es) you are considering.