For use outdoors only really
Indoors ive been running standard shock mount with 2mm limiters inside to reduce travel
There are a few reasons to use the 2 or 4mm lower shock mount, the main reason being more side bite and grip. Doing this will also make the car feel more stable when the suspension starts to work etc.
Indoors this isnt needed but you can do the same with the rear by unwinding your rear ball ends 2-3 threads and also fitting the alloy bottoms which will also reduce another 2-4mm from memory to provide more grip on rear
Were going off topic here so il stick to your original question