I don't get the joke but it's been a long time since I've seen a 97-03 Grand Prix that didn't look like it's front bumper cover was melting and warped. They look nice when they're young!
"In particular, every 6-Series model has "flared wheel arches and horizontal lines across the rear emphasize the cars' wide track and resultant surefooted handling." Wider is better, as we all know."
I think the joke is if you squint your eyes super hard, the new 6 GC is supposed to look GP-esque. Not sure if I buy it, but still laughed. Especially at the part that boostedguy quoted above me.