He said all cars were available to drive, so surely he tested a standard or at least looked at one to see the difference.
As for suspension modelling, that has to do with the physics, which he did cover. He said that a lot of menu options were locked out, which is likely why he didn't go in to details on those other features. Please note the Course Maker isn't even going the be in the game we get on the release day, rather it will be released in an update.
Just speculating, but cars and tracks are 2 things he had open access to, for sure, so we know he could have plainly seen the quality of them, just like how he commented on the sounds.