I have finally made the vehicle size edit more stable! I did it by making the scaling time adjustable in the Tuning menu:
Increasing this value reduces the time in which the resizing forces are applied, which basically means the car won't explode instantly. Note that you should NOT use it when you are not changing the car's size, because it makes the game lag terribly for the amount of time you set there and generally can break stuff. Also, on most cars the wheels still break off when scaling due to the L-Beam angles changing a lot. And increasing or decreasing the size too much will still make things explode, I can't change that.
I have updated the old resized configs so they are more stable and less shaky (I could use more damping thanks to more stability). Additionally I added configs for the cars for which scaling is the most stable:
Ibishu 200BX "Monster" - Big offroad 200BX
Ibishu 200BX RC Car - Small uncontrollable 200BX that drives terrible due to tiny wheels with almost no grip
Big I-Series - Well this speaks for itself, nothing really special apart from the fact that it explodes when you try to pop a tire for some reason
Small cheap T-Series - Can barely haul a trailer because the wheels are so low, it can't really turn, rear dually wheel sizes are mismatched, has a bumper-mounted coolant for some reason, generally it's a hilariously bad semi truck
Big fat heavy dump truck, it's so huge it can almost fit another T-Series inside, ground clearance is non-existent though
And that's it for this update, have fun with it like always!