LS25MKII and VT100MKIII was very nice... I did not have a VT100MKII to compare to the MKIII. I do not think that ARC went "backwards" with either of these upgrades. It is $1600 +S&H to take the VT100MKII to MKIII. I am going to try VT100MKIII at home in a couple of weeks. Unfortunately, we listened to the VTM-200s for 3/4s of the time, since the Proac Response 5s seemed to like more power.