This is a good deal for both parties, I can see lot of Buick GMC stores in rural markets not wanting to pull the trigger on 300-400k to meet image compliance. They know their bread and butter is trucks and SUVs so no brainer. The remainder are metro/suburbs where it makes sense to roll the dice on a Buick rebrand.
Buick has traditionally struggled to separate itself after the '10 brand re-org so it make sense to go in a different direction. How they compare to Cadillac is a big question now as they have done the same thing with bigger $. Do I have faith in Buick....
