I don't think oil slick is really needed but I guess if there's a chase sequence and KITT can't just get away with speed it'd be useful, but the main "classics" are a must. I think a good mix of reality and "fantasy" would work just as long as it doesn't get silly, like things seemed to get when KITT used the "magical microwave jammer of wonder and mystery".

No flying outside of turbo boost, maybe the amphibious aspect that was introduced in that one second (I think it was second) season episode and never used again until Knightmare 2000. It's tricky because KITT was able to do a lot of things, what couldn't the original KITT do? I don't think there's a need for a monitor/TV screen at all anymore and it might still work better than a holographic display as a replacement but then I can see how something that's actually there would probably be better. Maybe the windshield/windows could "change" to a screen or wait, KR2000 did that didn't it? Ugh... I need to laydown because it's a real pain in the backside to do this right now. I do know he inside should be more streamlined though.
Anyway, to go off topic (as if I already haven't), I was thinking last night that it might be good to show the work going into building the car including a little explanation or "science" behind certain aspects and abilities, such as turbo boost and a at least somewhat feasible explanation on KITT's turbine engine to go along with it. Maybe a few hints at a previous prototype that had to be deactivated.
Okay, I need sleep..... This post sucked. I should be fired or banned because of it.