Help me understand? Preload Spacer vs. raising Spring Perch?

[BiGJZ74]

What is the Difference between Raising the Spring Perch vs. adding a preload spacer to achieve lift?

 

[MJH19RAM]

Nothing is different, other than when you get a shock that raises the perch (like the bilstein 5100’s), the shock itself has different valving than the stock shocks do, so it’s likely they have tuned compression/rebound to make the ride a little less harsh given the increased preload on the springs. If you add a preload spacer to the factory coil over, the shocks aren’t tuned for it.