I’d say mid 80s to mid 90s, don’t forget the scary 90s vtec stuff, and of course the NSX
Riley, Triumph, Panhard, Hotchkiss, Innocenti, Studebaker
Relive the British Leyland 
between a more mainstream company such as bmw or mercedes or something like caterham or radical if the body designer permits them kind of body styles
I will just make on my own 
I am going to make my own company, but based on a mixture of 3 others: 1920’s Mercedes (assuming we can make supercharged 4L inline-4’s ), 1970’s Porsche, and 1980’s Nissan/Mazda… With a couple of ‘experiments’ thrown in (V12 Minivan anyone?)
Ford, Audi, Aston Martin, Ferrari
I don’t want to base my company on a particular company, but I want to design and produce the cars I love: american full-size cars. A huge and lazy V8 coupled to a sloppy automatic and mounted on a ladder frame chassis. Like the Chevrolet Impala and Caprice, Ford Crown Victoria, Dodge Diplomat, Buick Roadmaster and Oldsmobile Custom Cruiser. (and I drive a smart fortwo - kinda ironic, huh? 
)
And maybe later on some over engineered cars for the european market, such as the Mercedes-Benz W124 and W201. 
hi all you new guys welcome aboard.
That would be me - among others - so thanks! 
EDSEL! LOL
My '85 CRX was the greatest car I’d ever had up to that point in my life. It’s still the benchmark I use for everything else. The GTI I have now, I describe it as “it’s like a CRX with a back seat and more horsepower.”
I’d like to try re-creating Studebaker and see if I could keep it in business past 1966. Imagine the possibilities: a mid-80s Gen 5 Avanti, with a turbo V-6 and AWD . . . a New Beetle-esque 2003 Loewy coupe . . . a Conestoga minivan . . . .
I will create a french luxury car company, and I will try to compete with the german and swedish brands… Or maybe it will be interesting to create an american brand like AMC, trying to compete against the Big 3 (with more success I hope)… If there is any “Big 3”…
So actually my question is: Will we have a realistic context of the car economy and history, like 3 big brands in the US or in Japan, the fall of the british car makers in the 80’s, the rise of the korean in the 00’s, etc… ? IMO, the best thing would be, when you start the game, to have the choice between something realistic and something more random…
AFAIK, there should be 3 modes:
-with manufacturers based on the real ones, with realistic history context
-with random manufacturers, but with realistic history context (so you won’t have Big 3, but you’ll have oil crisis in 1973)
-with random manufacturers and history context.
Good, with these 3 options, the gameplay possibilities should be almost endless 
That’s the broad idea, we’ll see how it ends up once we get to that bit though.
I think I might do a mix of someone like Honda crossed with a big German company such as BMW. That would be quite entertaining, producing cars for the future (eg. hydrogen, hybrid, electric) while at the same time producing really high quality executive cars that aren’t that environmentally friendly. And what would be good would be adding elements of my Eco vehicles into my mainstream cars. So for example a 3 litre diesel saloon with a hybrid motor.
I would love a company well known for their innovation such as pre-1980 Citroen but with the class and reliability of a Subaru… Think of an evolution of the Citroen XM and its hydropneumatic suspension with the boxer engine of an STi. Yummy!!!
I like where your going with this 