I have been using fewer and fewer mods as of late. I still keep them so I can throw AI drivers into them and have very diverse race lineups.
The vast majority of mods are not accurate at all. As you pointed out, they almost always have way too much grip and are way too fast. I don't understand it. Some of the more active modders spend so much time converting cars to work inside of Assetto Corsa, yet when it comes to just punching in the proper power numbers and making sure the car isn't too grippy on a skid pad, they can't be arsed to spend 30 minutes getting it right. I've come to the conclusion there are two reasons for this. A) They honestly don't care if it's accurate or not and B) All they want to do is get their name out there..."Oh, look how many cars Mr. X released." Or, "wow! Mr. Y released a whole bunch of awesome old cars!"
The cars that will usually be proper mods with dozens of hours of testing and refining will be the ones you find on Race Department. However, even some of those may not necessarily be 100% accurate, but they will be 100% scratch built...These Facebook Modders, as I call them because that's where they release everything, are always using ripped Forza models or ripped 3D models from another source. They often have very decent 3D models to work with and they ruin them by slapping ridiculous physics onto the cars. It's a shame.
I've come across those before...and then you need to make 5 posts in order to see the link - just so they can pump up membership numbers and post counts. If the mod was any good it would be well known by now anyway. 👎
Well, the Auto Union Type C looks pretty nuts too. 
*pedant hat off* 
