I believe the Jan 3 one is visually tweaked (I'm using it). Any of the bootanimations should work without flashing. Just open the zip, look in the data file and extract just the bootanimation.zip file. You can then transfer it to the phone, and put it in either /data/local or /system/media. The rom's normally have it in /system/media but if you put it in /data/local it will look there first. It has to be named bootanimation.zip.