Yes, the Kronos is definitely very much an M3 XPanded. I had an M3XP module last year, then I tried the Krome in a store and listened to many demos of the Kronos preset sounds. Korg blew up the German piano (which also sounds very much like the M3 XP 4-way grand) to 2 GB size due to very long samples, which however doesn't change its general timbre. At least regarding the PCM orchestral sounds like brass, strings, woodwinds, a lot is nearly identical to the M3 XP. But IMO it is the ample space for additional sample libraries which can turn it into a great sound monster, not so much the on-board preset sounds.