I dont know about it being really rare as it was all over back in the dau when it was finally released on Ten, but this track was massive for about 8 months on white label, so the buzz had sort of dies down it it by then. I think this track is more sought after, hence the price of it. If I was to buy it again I wouldnt pay more than 7 quid for it, But the white label, well thats different because if you listen closely to both records, they a different!!
They re-did it for the release. I reckon you'd get more for the original white label of it. Mind you I wouldnt sell my copy. Check the Todd Terry remix out as well, thats seriously large as well.
Piano Passions is rare yes, top tune as well. Whether its sought after as well is another story but I've seen it about occasionally for about 15 quid.