How is 2007+ different from other 2005+

I think the only difference is the 2007 came equipped with TPMS.

The 2007+ Mustangs also have a stiffer chassis due to different welding and addition of a few braces (It came with its own version of the G-trac brace I found out the hard way), TPMS as the previous post stated, but the most distinctive (and important) difference is in the engine management which is different and requires a separate programming / tuning from the 05-06 models. If you notice you have to specify in a lot of performance upgrades (ie superchargers, tuners / cai combos) what years you have because of this difference.

This of course is all in addition to any cosmetic things like packages, colors, HID / interior lighting etc.

AC control knobs that don't pull off. Silver Horse still do billet replacements but it's harder to change them.

3.55 rear end was stock on the 2005 before it became an option.