I tried overclocking the 348 with 352 firmware. Everything goes well
change of names, identification, speed detection, etc... But when i tried to burn cdrs at 52x or any other speed, it failed with weird errors & drive just spinned without writing. Tried the burning in Nero 5.5.10x. Btw, you cannot update the firmware with Samsung's native utility so i used mtkflas for win.
Hence it's a drive with a better flash rom, it was able to switch back and forth in firmware without any issues.