I listened to all the iTunes snippets through my car stereo last night - until then it had been via my iPhone or iPad. (with and without headphones)

Big difference. The songs do indeed sound fuller - the bass and drums on The Devil's In The Temple sounded immense.

Rollercoaster's weak vocals on the chorus were not as apparent as the music comes alive through a decent speaker system. They're obviously still the same vocals, but there's enough energy to the music to carry them, if that makes sense.

Sounds an obvious thing to say, but how you listen to the songs does shape your opinions of them. A subtle instrument heard via your phone, for example, can suddenly come alive through better speakers and really add something to a song.