Hi everyone,
my main goal when creating Vehicle Manager has always been to respect genuine performance settings for each car, so that my tools (and me) can't be responsible for online cheating/disturbing.
I love this game AND online mode - unlike people such as Kurgan, or Dredgy and many others.
Since 1.14 I've added a speed limiter setting, that allows to set lower speed as original to enhance car realism. But already modified speeds (which are bigger than genuine) are considered as invalid data. So it's not a bug, it's a feature.
Now, if anyone wants to take responsability, you know there's a xml file in my Modding Tools which can be modified to go beyond the rules. I won't provide any support for this, as I'm sure some of you have already altered it to make other slots to appear in Vehicle Manager.
So, there won't be any 'fix' for this. But thanks for bringing this point out, you have now an official explanation :)