How race car drivers helmets affect their race cars performance and handling???

If you are a motorsports fan, you should enjoy this video.
When I was working in NASCAR back in the late 90's and early 2000's, for Simpson Race Products
most of the drivers had been switching over from open faced racing helmets to closed faced helmets.
Some of the drivers were having a difficult time with the change.
Sometimes when the drivers cars weren't handling the way they liked they would bring me their helmet
to work on. Like Dale Earnhardt Jr and Tony Stewart and Ward Burton by some miracle, after I worked my magic. Their helmet's fit better and their cars drove better??? Watch this video for details.