Our DAC2 D/A converter will provide exactly the same performance at either 96 kHz of 192 kHz. However, in most cases, many A/D converters (used to record the music in the studio) achieve better performance at 96 kHz than they do at 192 kHz. But, these differences will be very small.
If a track is available in both a 192 kHz and 96 kHz format, there is a very good chance that they are both derived from the same 192 kHz master. Therefore, the 96 kHz version will be no better than the 192 kHz version. If the master was 192 kHz, the 96 kHz down-conversion may be slightly lower quality (due to the extra down-conversion process). But any differences should be entirely inaudible because the down-conversion process is highly transparent when executed with a high-quality mastering system.
Bottom line, we would not recommend spending extra money to get the 192 kHz version if a 96 kHz version is available. Buy more music instead.