So, in my modified ZR-350 post, https://www.simpleplanes.com/a/2m1c89 , I'd accidentally made a system that acts like the Skyline GT-R's ATTESA-ETS system.
I didn't even know about it until i took a look into the ATTESA-ETS system, and compared it to my ZR-350's traction system.
They work the same, the computer detects rear wheel slip, and applies torque to the front wheels.
This, yes, indeed also causes understeer.
Now, i didn't know how i made this exactly, but it has something to do with the low power gyroscope that helps with keeping the car on the ground.
I'll release a faster version of that ZR-350 soon, all i have to do is tone down some XML mods.
If i turn off the gyroscope, the vehicle becomes uncontrollable and will spin if any loss of traction occurs.

The gyroscope, what i believe it's doing, obviously it's keeping the vehicle stable and trying it's hardest to level it out, but it's also maintaining traction with all four wheels by keeping the wheels from kicking up into the air, which is what it'd usually do without the gyroscope.

UPDATE:New R32 with the Attesa ET-S system implemented, instead this one doesn't auto-correct, and acts like the original. Except it's much slower at applying torque to the front wheels.