Shock Explosions from Bump/Rebound Stiffness

Okay so, I'm trying to make a D15 that can literally hit anything and not be severely damaged, I already have the front suspension, and frame taken care of, it's the rear suspension giving me issues. The leaf spring was being compliant. As you read the file, you'll see I've change the beam deform/strengths to be virtually impossible to break unless you really go 270mph into a wall, and even then you still might only pop the tires/break the body. The frame and front suspension are also coded this way, and they're rock solid/durable.

*Take Note: I'm trying to achieve an affect where when you hit a hard bump (like a speed bump) at moderate/high speeds, the leaf spring compresses and then slowly comes back up, this is to reduce the amount of bouncing that normally comes after the bump.

My problem is with the rear shocks as I have named "Rear Extreme Condition Shocks" (cause that's what they are, meant to handle extreme conditions) are really stiff when it comes to the rebound/bump stiffness. Now I have made these slightly higher in stiffness compared to the front (that's just a habit of mine when I tune cars both in this game and Forza). The problem comes when the car spawns, you'd think the car will just spawn and sit there happily. Nope, it sits for about 2 seconds, and the shocks explode ( and sometimes takes the whole car with it).

When viewed in 100 times slow mo, you see the car initially spawn fine, but once it hits the ground and the leaf springs compress a tiny bit, the shocks stretch out all the way and violently shake and eventually the beam breaks. I have no clue what causes this so I hope someone will understand this.



EDIT: So I've found that reducing the Bump stiffness to like 19000 instead of 30000, and slightly reducing the rebound and fast rebound stiffness, I've managed to make the shock stable again. But now the question becomes why do very high values of stiffness cause instability with the shocks?