PCPD Special excels in longer distance tracks (slightly higher top speed). Or when the track involves numerous tight turns (PCPD Special is phenomenal at making instant sharp turns, and due to never leaving the ground, can make turns where other vehicles simply can't). The Nighthawk just has unmatched acceleration. And is somewhat more likely to survive a collision (just as long as it's not a head on collision).
I'm pretty sure the "higher top epeed" has to do something with how much the Gt Carbon Concept weighs, The Carbon is much lighter than the Nightawk, which does indeed give it a higher top speed, if I were to test this online there really isn't a point, the Carbon Gt Concept would still be outclassed by the Nightawk due to its really good acceleration.
I'm honestly not to sure, the toy variants, they're obviously slower and have more air time, but handling wise I'm not to sure about, really the only difference between the two is just speed and airtime, everything else is just the same, for me anyways
I forgot to mention that the toy cars are much stronger than regular cars. They can still be destroyed by playing events such as (Marked man, Road rage)
You're not alone. I miss the racing games from the PS2 era. They were just fun to play. Progression was rewarding. DLCs have ruined racing games. Modern racing games just don't have a fun progression and reward system anymore. You just get handed out cars for basically nothing. The only modern racing game that I kinda liked lately was Wreckfest.
I bought some of the recent NFS games but I still play NFS Carbon (2006) from time to time. The new games seem hollow to me. I haven't really looked into Horizon very much but it doesn't sound too much better.