The original pickups were custom wound DiMarzio from 2001-2006 and similar to the Air Norton/ToneZone
2005 introduced the compensated nut (on the Buttercream Limited Edition), with standard production having the compensated nut beginning in early 2006.
2006 introduced the D-Sonic pickup in the bridge with the original custom-wound neck pickup.
2008/9 introduced the CrunchLab/Liquifire pickup combination
2012 stainless steel frets became a standard feature on guitars ordered in January (began shipping in May/June)