Thanks for the explanation.
I did it before and I did it again. I added custom object channel. I added custom collision preset, which ignores vehicle preset and set vehicle preset to ignore this new collision preset. Then I tried to repeat all test cases, which described above, again(with skeletal object and box and with scaled car). There are absolutely no differences in results. Maybe I’m doing something wrong. But if so, can you make a working demo to show me correct setup?