Samsung releases seem to be confusing lately - at least for simple me. Samsung released SH-S223B, which according to the very valuable input of Ala42 has a Mediatek chipset with i8051 CPU core. Then it released the SH-S223C which (again thanks to Ala42 for the ID) has a Samsung SA57821B03 controller with an ARM CPU core. Then for its new x24 models (SH-S243D SH-S243N) it switches back to the same Mediatek chipset as the SH-S22B. Which brings us to the obvious conclusion: It may be possible to crossflash the 223B to a 243D if the chipset in both models is the same revision. Previous Sammie models have been practically identical apart from chipset revisions, so it could be possible.
Obviously the benefits of such a crossflash would be minimal. My 223B can be inconsistent @x22 with my favorite SL media (Taiwanese Verbatim MCC 004). Managing to burn these @x24 will only cut a few seconds at best from burning time, and burn quality may suffer further. But I'm very tempted to try, just for the hell of it!