How to Replace Door Speakers in Silverado - YouTube
Amazon.com: Harmony Audio Compatible with 2006-12 Chevy HHR HA-R65 6.5" New Front Door Replacement 300W Speakers with HA-823006 6.5" 6.75" Speakers Adapter and HA-724568 Factory Speaker Replacement Harness : Electronics
The Big Guide To Car Speaker Sizes (Plus Great Installation Tips!)