I now graphs don't necesarily match the real world but according tgo this chart, the PASM on Sport mode achieves harder/stifer dampning levels than the -20mm.

So the ride can even be stiffer with the PASM in sport mode which may seem contradictory to many people... if the PASM in sport is stiffer then why is the -20mm car faster around the tracks? Well, I believe the problem is that the springs cannot in turn vary their stiffeness and resistance to match the variable dampning sttings of sport vs normal so the spring rates are not as precisely matched to the shock's dampning as in the -20mm, in order to work for both normal and sport settings, the springs have to be less specific for the shocks since the shock stiffness is not always the same.

Its like changing the shocks in a car back and forth from sportier shocks to more confortable shocks while keeping the springs unchanged, even if the shocks are very sporty, if the springs are not precisely matched to work as one, then a slightly less stiffer shocks can be superior if its got the perfect springs for them and specific to them. So while dampning may get stiffer than the -20mm its still not as effective overall as de -20mm (besides the rear LSD) due to its compromise for versatility and variable dampning settings that the whole suspension as a unit has to make. Just my opinion anyway.