How much technology is approriate for a race car? That depends on the purpose of the racing.
Formula 1 Grand Prix racing is rightly considered the pinnacle of motorsports technology. It's the leading edge, the fastest cars, the best drivers, the ultimate in everything.
There was a time where virtually anything the race teams could develop was okay. Active suspensions, multiple onboard computers, traction control, two-way telemetry, you name it.
Most of that technology has been outlawed in the name of competition. Now F1 cars can have only car-to-pit telemetry, not pit-to-car. That prevents mechanics from tweaking the car as it whizzes by, which happened during the Monaco Grand Prix two years ago. David Coulthard's McLaren was leaking oil so the team's engineers closed a valve remotely, without so much as a pit stop.
Is that appropriate technology, or does it just spoil the racing? Depends on your point of view. Is the purpose of racing to advance automotive technology or to entertain fans? Make no mistake, those are two very different goals.
Now F1 cars have less technology than the average new family sedan. Stuff you'd buy for your Camry isn't allowed in the F1 paddock. And don't even think about NASCAR (please); that's as low-tech as you can get and still call it an automobile.
Personally, I love having the data-acquisition system in my own car but it's data I can only download and analyze well after the race is over. I'm not sure I'd like "live" telemetry. That would spoil some of the fun.
Should racing be high-tech or low-tech? Let me know what you think.