@Severin
I'm not the author of ADRipper but I think this has to do with the programs's plugin architecture. ADRipper always supplies chunks of raw 16-bit stereo PCM input, and lets the plugin do whatever is useful with the data.
ADRipper would have to provide some kind of internal AIFF saver that bypasses the plugin architecture and only grabs and renames the CD tracks. However, this is not the case - so you really need my AIFF plugin
However, there is practically no overhead: the plugin simply writes uncompressed data to file as ADRipper grabs the track. The internal saver wouldn't be much faster.