Problems With Import Discs ...

So ... I bought a delux edition copy of One Direction's Up All Night at Best Buy and decided to grab some imports for extra tracks etc. I have the US, Mexican and Japanese editions and a couple of things have struck me as odd. Here's a comparison of all 3 discs:

US - The sound is great and the packaging is fine. It comes in this hard cover packaging with an open paper slot for the disc to be stored. Nothing to protect the disc, but that's typical.

Japanese - The same exact sound quality as the US, but the packaging is better. The hard cover packaging has a nice glossy look to it and the disc is now protected by a sleeve.

Mexican - Well, my ear was hurting by the middle of the second song. I'm guessing the bass got boosted a bit too much. The only other time I problem with the "loudness" of a disc was when I put in the Stones' Forty Licks. The disc came in a jewel case, which is nice ... what I most like about it. And then, when put the album on iTunes, a number of those songs developed a problem where it skips in spots. This isn't the first time I had problems with skips, but it's very rare in the transfer. And each time I reimport the disc, it's always a brand new skip and the other one is repaired.

To talk more about iTunes. I've had the exact opposite occur to me as well. My copy of OK Computer by Radiohead had a very small skip that was noticeable but listenable. I imported it and the skip wasn't there. Struck me as odd but I was pretty thankful in the end ...

So, I'm curious if some imports of albums have this problem or did I get a bad disc?