Remove Envoy Bumper
 

Need help to remove front plastic bumper facia from 1998 Envoy.
Plastic is in perfect shape and don't want to break it. Facia is 17 years old and probably getting brittle.
Don't see any obvious attachments. Assume its like the grill and snaps into place with metal clips?
Need replace HID ballasts that are mounted on top of metal bumper sandwiched under top portion of plastic facia.
Pictures don't show how far ballasts are mounted forward. Removed headlamp assembly's, but no joy as ballasts are tucked forward of headlights. It appears that ballasts are attached to adapter that is in turn bolted to bumper / support, by 4 cap screws that can be seen in pictures.
These ballasts are about twice the size of modern ballasts.
Pictures taken from left wheel well, bottom of ballast heat sink is visible. As you can see its on top of bumper support...