I have 78 added vehicles and shared handling does absolutely nothing. In my case, it's the position of the handling line itself.
If we can somehow 'shift' handling line positions without actually moving their spots (without jeopardizing other vehicles' handling lines), using the Limit Adjuster, then hopefully the suspension bug can be solved. For now, there's nothing I can really do about it.
It might be dependent on one's system, but I highly doubt that because:
Weird. I have currently 70 new vehicles added without replacing, no glitches at all, everything works fine.
I don't want to remove any vehicles, because not only may that compromise other vehicles due to the positions of their handling lines being moved including the afflicted ones, I don't want to remove any of my vehicles on the count of a bug that has a chance to be corrected.