BTW, I don't think there is a 150 year old Grand Marnier. It was invented in 1880. And according to this site, probably not.
The next level of Grand Marnier is the Centennial Edition, or Cuvé du Centenaire, which is made using the same technique as the Red Label, but substituting 25-year-old Cognac for the normal Cognac used. This type of Grand Marnier costs nearly 200 US dollars (USD) per bottle and is meant to be drunk on its own. At the top of the heap is the Grand Marnier 150, a blend of Grand Marnier made using the highest-quality 50-year-old Cognac. It costs in excess of 200 USD per bottle and is often very difficult to find – indeed, an advertising campaign for it used the line: "Hard to find, impossible to pronounce, and prohibitively expensive."
That’s funny. I thought it was the age, but it was just the label. And I confess that the few times I’ve had it, someone I didn’t care for much was picking up the tab. Does that make me a bad person? It does taste considerably smoother that the regular stuff. I believe I could tell the 2 apart in a blind fold test.
As for audiophiles, I’m with you. My primary listening vehicle is my iPod. And I’m a musician with an above average ear. It’s not the sound quality I care about the most, it’s the performance. CD or vinyl, doubt I would pass the blindfold test.
Now its $1000 audiophile grade power cords. Not needed IMHO, nut you will find a difference between the $5 hunk of zip cord and a large, (12 or 14 guage) cable. You don't have to spend huge amounts to get a noticeable improvement in bass response, dynamics and imaging.