Buick Regal, almost full analogue of the Opel Insignia. Full description see here:

How to remove front and rear bumper Opel INSIGNIA (from 2006).

Front bumper

front bumper mounting scheme Buick Regal (2011-2017)

Rear bumper

rear bumper mounting scheme Buick Regal (2011-2017)

 

How to remove front and rear bumper Buick Regal (1997-2005)