I can’t comment on this comparison but can give you an update on the 40th Anniversary SL Kraft 300 Mono-blocks compared to the standard Kraft 300 Mono-blocks and the D’Agostino M400 Mono-blocks. I received my 40th Anniversary Kraft 300 Mono-blocks in December 2021 replacing the standard Kraft 300 mono blocks and have around 1500 hours on them. Out of the box there was a noticeable improvement in clarity and transparency and they continue to get better exceeding the performance of the standard Kraft 300 mono-blocks. The biggest improvement is in the midrange providing greater insight into vocals, piano and all other musical performances with better layering within the soundstage that communicates their location within the soundstage. Simply stated the music performance has greater palatable presence. The other improvement is timbral and tonal accuracy with a greater warmth and naturalness to the sound especially listening to violin concerto’s, saxophone solos and vocals. There is also greater inner detailing improving my musical experience to hearing musical details never heard before. Another improvement is with the attack and dynamics of the musical performance which makes the performance sound more real or as in a live performance. In comparison to the M400, the 40th Anniversary SL Kraft 300’s are very close in overall performance and within 90-95% of the M400’s sonic characteristics at a lower price then the new M400MX4. The old version of the M400’s have a better grip on the bass performance and a slight bit more slam but the 40th Anniversary Kraft 300 version is not far behind in these areas and definitely comparable in the mids, clarity and transparency. I haven‘t heard the new M400MX4 but have to assume it is much improved over the standard M400‘s. Nevertheless, I am extremely happy with the 40th Anniversary SL Kraft 300 Amps and they are a key contributor in my systems great performance keeping me engaged in the musical experience at a reasonable cost.