KITT should be a hypercar, and pushing the envelope not just of the possible but the plausible. They should also, however, do their best to stick to practical and not turn it into a CG-fest. Allowances for possible-but-cheaper-in-CG stuff like the '08 pilot's chameleon effect -- changing the color and trim package. But since KITT is supposed to stand out, just changing colors wouldn't be a good disguise -- it would be of more practical application as a camouflage mechanism (blending into darkness or terrain better).
May be hard to remember now, but the show premiered right at the same time as the Third Gen Firebird. It was a complete redesign, done in consultation with Learjet. Most aerodynamic car GM ever produced. First with fuel injection, first with a four-speed automatic gearbox. Take all of that and cram in the turbine engine and all the gadgets and you had something that was damn close to an American hypercar, before the term really existed (and certainly before America was making any hypercars).
I don't know what car I'd currently recommend for a new version of KITT (or whatever designation). Maybe one of the new Porsche 918 Spyders. Maybe a Nissan GT-R. Something rare and exotic and beautiful and sleek and dangerous and already full of cool innovations while still having room for more to be crammed in. Not a Mustang. I have a warm spot in my soul for Mustangs (except for the 2nd and 3rd generations -- and don't know yet how I feel about the 6th-gens)... But not for KITT.
More important, though, are these two points: 1) The Mission -- The original concept was a little Batman-y. The lone vigilante (albeit with surreptitious support) taking down villains who used the letter of the law to defeat the spirit of the law, helpign those who could not help themselves; 2) The Rapport -- The byplay between The Hoff and KITT was a lot of what made the show, like any buddy-cop story with the straight-laced long-suffering partner and the laid-back rule-breaker. The world and technology have changed a lot since 1982. That's part of why the 2008 sequel fell flat -- they couldn't redo the same thing as the original as it didn't fit any more, but their take went too big. There can be a larger organization doing big global things, but the show needs to be intimate -- about the lone vigilante and his partner/steed, mostly unsupported, out there in the wilderness (a wilderness that needs to be defined). A techno-Western. Yojimbo.
I think that's the biggest challenge facing any reboot/continuation. Where is the hero operating? Who is he acting against? How does he evade detection by the legitimate law-enforcement agencies? It needs to be something relatable to the audience. Maybe even casting a more favorable light on Hollywood's favorite whipping-demographic, the impoverished non-city-dweller. The farmer who's had his land ruined by fracking, or seized by Monsanto. The dead miner's family trying to get the mine owners' chokehold on the community off. Look at Leverage. They did this very well. Now try to find a way to do Leverage mashed up with Knight Rider without being derivative. If they can pull that off, I'll laud them from the rooftops. Difficult, but not impossible -- if the creative team give a damn about the property beyond hoping for a cash-out.
--Jonah