Faults per 100 vehicles is a fundamentally flawed criteria, it penalizes features.
The more features a vehicle has the more potential and real faults. Conversely a lack of features results in a high score.
I think this is appropriate, if you're measuring reliability. More complicated stuff has more stuff to break, and you'll end up spending more money over time to keep everything working.
There might be some value in splitting it into "major" (can't drive the car or can't drive it safely) vs. "minor" (electric window won't roll down, heated seat doesn't work).
A fundamental problem is emerging where something that should be "minor" (touch screen broken) keeps you from driving the car - you need that one screen for shifting gears, climate control, windshield wipers, etc.