I seem to recall a crash test in the 90's, where a Hyundai Sonata and a VW Polo where crashed into each other. While both had airbags, the Polo afforded FAR more protection than the much larger Hyundai. Potentially, the Polo without airbags may have actually been better than the Hyundai with???
I sold an 96 Legacy wagon (NA) I had to a 16 year old girl touring the country. She was looking at the Legacy, or a Starlet. A week or so after I sold it, the girls aunty phoned to thank me for talking them into a bigger car - the girl was turning across SH1, and pulled across the path of a car, and the front left of the legacy was hit so hard, it spun fast enough for the back corner to hit the same car! An airbag in the steering wheel would have done nothing/little, but luckily, the legacy took the brunt, and only gave her some massive bruising from the seatbelt, and minor cuts from glass and flying plastic. I can't imagine a Starlet/Logo/Mirage etc for similar money, doing anywhere near as well.
I'd certainly be looking at crash data etc, if I was concerned about safety.