The stiffness of the shocks for compression and rebound should match the spring stiffness
The driveshaft alignment is critical from the standpoint of mechanical efficiency. Loss of efficiency can rob power from the drivetrain due to the generation of vibrations and harmonics that are also damaging to the bearings. The overall general rule is that the angles between the driveshaft and both the pinion shaft and the transmission output shaft need to be equal and in opposite directions. The less angle the better.
The driveshaft doesn't know which view these angles are resulting from, just that they are equal and opposite. If we have a top view difference in alignment between the transmission output shaft and the pinion shaft and they are parallel, then the angle to the driveshaft created by that misalignment might be sufficient to provide the needed angular differential needed for loading the U-joint bearings and reducing negative harmonics.
A 1 1/2-inch top view misalignment with a 44-inch driveshaft results in nearly 2 degrees of angle at both the tranny and the pinion shafts. The engine should always be aligned perpendicular to the rearend and/or parallel to the centerline of the car. This would mean we could align the driveshaft from a side view inline with the tranny shaft and the pinion shaft with no angular deflection.
5. Setup Balance
Balance is spoken of in all types of motorsports these days, even F1. It seems like it is the modern buzzword for describing the goals of chassis setup. Here is an explanation of balance related to the dynamics of the race car.
If the brake bias is at or nearly out of range for the adjuster in your car, it is time to
The setup we choose needs to be arranged so that the dynamics are balanced between the front and the rear suspensions. Each suspension system desires to do its own thing when lateral forces are introduced from the car going through the turns. These desires are directly influenced by the spring stiffness, location, and spring split, the sprung weight the system has to support, along with the moment center locations and other settings.
Each end has its own moment arm length and resistance to roll as well as other factors. The bottom line is that at mid-turn, each end will want to roll to its own degree of angle. That is the best description of the result of the dynamic force that influences each system. If those desired angles are different, then we term the setup unbalanced.
Unbalanced setups exhibit easily observed characteristics, such as unusually high degree of wear and temperature on one tire versus the other tires. The car may or may not be neutral in handling, but the handling will not be consistent. You must try to determine if your setup is balanced and then if not, make the necessary changes to bring it into a balanced state.
Once you have evaluated all of the above and feel fairly confident that the car is set up correctly, you should then work to tune the transitions into and off of the corners with the shocks. The overall work that a shock does is to resist the rebounding of the springs and control the speed of compression. Since the spring promotes rebound and resists compression as inherent properties, then the shock rate of compression control must be less than the rate of rebound control.
The amount of difference you need is directly influenced by the installed motion ratio of the spring and the spring rate. A very soft spring would need more compression rate and less rebound rate, whereas a stiff spring would need a lot of rebound rate and much less compression rate. These are the general rules unless you are trying to "tie down" a corner. However, tie down shocks are becoming less and less desirable.
Shocks affect the motion of the corners of the car and therefore the placement of loads during transitional periods. If one corner of the car is shocked stiff, then as that corner desires to move in compression, more load will be retained by that corner as well as the opposite diagonal corner of the car during the compression cycle only.