Good, a 90s kid. You are right, I wasn't born in 1994, but rather 1998, so yeah, I didn't get to enjoy those. You really seem to not like the sort of pop culture from the early 2000s and I don't blame you, I'm the same today. The reason you chose not to play those, new at the time, NFS games is probably the same reason I choose not to play today's new NFS game that much.
But why the hate, what's wrong with modifying cars? Trust me I prioritize the engine above all, but a bodykit and a spoiler/wing are gonna improve the looks, as well as aerodynamics.
Cars with vinyls can look good as long as it's not a cheap job, of course. I am playing U2 right now and not all of the vinyls that the game offers you are bad, some of them look masterfully done. And this is true for the bodywork as well, as long as you're not going for cheap products, your car can look good.
And just to correct you as well, there is no such thing as "the real NFS", they are not really obligated by anyone or anything to do the same thing over and over again, just because you don't like the change it doesn't make it bad. They just chose a different angle, whereas older NFSs from the 90's were more Supercar centered NFSU and NFSU2 were more import sports car centered. I wouldn't put a spoiler/wing or a bodykid and some vinyls on a supercar, it's not necessary, they look flamboyant enough. If it's manufactured by the same company that makes the car, fair enough, otherwise, I wouldn't.
And I really doubt that the import racing scene at the time was influenced by F&F. I think it was more like F&F taking inspiration from it, rather than cause it.
I just don't understand people that hate any sort of rice on cars. Please, explain to me why is there so much hate for ricers. Why would a car with a very powerful engine and expensive and well made race inspired cosmetic enhancements be so hated? You can just ignore everything from above if you want, just give me an answer to this question.