Yes you can change the driver names and the nationality, choose tracks and cars, laps, weather, track condition ... And yes this all stay during the championship.
You change all that in the vanilla game.
Every created championship is saved as a file in documents/assetto/champs.
So if somethig is wring or you want to change during the season it`s still possible by editing this files. But like said normaly not needed.
What you can`t do is adjust the drivers talent/strenght. This is only possible with CM i believe.
But my "trick" is i know already which fake driver in AC is fast and which maybe not. So every time setting up a championship i try of course replace the strong AI drivers with there strong real life counterparts.
Doing so i get not 100% accurate results but at the end of the day a Senna, Schumacher, Mansell .... will drive for the win.
Another thing is you can give the cars weight handicaps. So here you could "cheat" a bit agains the weaker drivers. Like i mentioned before in some series its important, because some cars are stronger than others for example the DTM 90s cars are very uneven.
Once set up there are only 2 important things you must pay attention to.
For example you drive a FIA GT 2003 race and you have set the AI difficulty/strenght at 95%.
Next you want drive a Porsche Cup which you want drive at 93%. So just before the race start you have manually to switch the strenght from 95 to 93%.
You can imagine driving 35 championships at same time i can`t remeber which i drive at which strenght.
So setting up a Champinship i just name them as follow:
GT 3 Euro 97% or CART 1999 92% and so on..,,,
Its also worth to adjust the AI agressivness from series to series.
All open wheelers and very fast cars should have agressivness below 70. Otherwise you will probalbly not finish the race
While slower touring cars or classics you can crank up at 80 and higher. So they will sometimes fight each other. Yes even AC AI can do it
Last but not least cars like GT3 category are good at 75-80 agressivness.
But all those setting are also a personal taste .... just try
The other thing you must do is - after every race to wait untill the AI has finished and the results screen appear. Otherwise its possible the progress will not save.
So you are interested in FIA GT 2003 - thats among the best choice you couldt have, because its based on the Race Sim Studio GT Pack.
And this content (pay mod) is among best you can get in AC. best quality in visuals, sound and physics.
As this content is a paymod you have to buy it from RSS. You will see due the licencing issues the cars has false names and logos.
But here at RD you will find a "patch" converting this into the real world thing.
As i can remember you can get all the real tracks for this particular season.
Otherwise as there are all free mods i can upload the whole track pack if you want. All tracks with working AI and newest updates if available in the www.
i could even upload the ready championship file. It should work, so you just need to modify that by your wishes.
ufff..... that was morre stuff i originaly wanted to say
I will upload some screens if you are not familiar with the custom championship mode.