Don't have 400GB card, but as you know, every manufacturer of devices supporting this card format (either smarpthone or DAP) suggests they can support up to 2TB, whenever these cards become available. So, if there is a limitation, it's gotta be firmware based. In general, not much of a sound improvement, uniless you are dealing with headphones that need more power, and the improvement is all part of the synergy with more power hungry transducers. But relative to P2, I hear a little blacker background under the same DAC filter setting between two daps. Not familiar with PS. with P2/P2mk2 there are 6 filters available with ak4497, you can go from digital "sharp" to a smoother "super slow". Not a very drastic change, but a trained ear with a high res IEMs can pick it up. I never found P2 to be smooth, it's neutral and more revealing. LPG vs P2/P2mk2 have a lot of similaries in technical performance, maybe P2 soundstage is a little wider. But in terms of a frequency response, LPG has a slightly boosted mid-bass and a little more sparkle in treble. Just keep in mind, LPG sound will be as is, while P2/P2mk2 can be fine tuned by switching between filters. For some reason, I found filter changes to be more noticeable in P2mk2 vs P2. I did talk about P2mk2 being faster and tighter, and P2 is already there as well, but P2mk2 blacker background tightens the sound (faster attack/decay). Again, keep in mind, I'm using Sharp filter, while switching to super slow relaxes the PRaT a bit, making it more musical. Sorry, I can't related to PS since I never heard it, but remember people were referring to it as more analog, smoother. Heard the same about Calyx M. Majority of the DAPs today have neutral and more digital sound, though WM1Z stands out and so does SP1000 CU.