Theshanergy, i looked a little at your script for the suspension and there is a little tweeking needed :
// shocks
var FaxleHeight = ( ( wheel_FL_height + wheel_FR_height ) / 2 );
// ( 0.19 - ( FaxleHeight * 0.9 ) ) - correction for axle height, witch is separate
// ( Math.atan( ( wheel_FL_height / -1 ) + 0.18 ) * 0.48 ) - for suspending a single wheel - axle rotation around forward/backward axis
var shock_FL_spring_height = ( ( Math.atan( ( wheel_FL_height / -1 ) + 0.18 ) * 0.48 ) + ( 0.19 - ( FaxleHeight * 0.9 ) ) );
this.geom.move_joint_orig(this.shock_FL_bottom, {z:shock_FL_spring_height});
var shock_FR_spring_height = ( ( Math.atan( ( wheel_FR_height / -1 ) + 0.18 ) * 0.48 ) + ( 0.19 - ( FaxleHeight * 0.9 ) ) );
this.geom.move_joint_orig(this.shock_FR_bottom, {z:shock_FR_spring_height});
var shock_RL_spring_height = ( 0.1 + ( wheel_RL_height * -0.6 ) );
this.geom.move_joint_orig(this.shock_RL_bottom, {z:shock_RL_spring_height});
var shock_RR_spring_height = ( 0.1 + ( wheel_RR_height * -0.6 ) );
this.geom.move_joint_orig(this.shock_RR_bottom, {z:shock_RR_spring_height});
The suspension on the front ones where good, only, you need to add the axle up and down movement too, to have a perfect fit of the shocks tips on them.
Thre rear ones had a little something missing ( a minus ? - you probably forgot, that the pivot point/origin orientation was the same as on the front axle, but rotates in the other direction ) ... aether way, i played with it and there ya go - paste the whole section on the script for the old one and make a repack - these fit like gloves.
P.S. - best when making animations like these, is to first compensate the axle height and when it looks like it fits, then add and tweak the shocks/springs (mind that you have tweak the constants for both after the addition). But dont worry, it took me just 8 min. to set them both right like this, so you can do it purely empirically, by try and error constants changing.
Also, maybe adding another animations rotation for the front shocks could be added too - the rotation around the left/right axis (normally the X axis, if Y faces front), so that when the axle goes too low, the shocks fit the thing even when looking from the side perfectly (best to use both the height and tilt parts that there are, but in some * 0.12 -- * 0.07 or so intensity) .. something like this added (doe, it already sits nice, so it musnt be there) :
var shock_FR_spring_tilt = ( ( ( Math.atan( ( wheel_FR_height / -1 ) + 0.18 ) * 0.48 ) + ( 0.19 - ( FaxleHeight * 0.9 ) ) ) * 0.12 );
this.geom.move_rotate_orig(this.shock_FR_top, shock_FR_spring_tilt, {x:0,y:1,z:0}));