Metaphors for Mercury...
Mercury will offer style and sophistication that Ford does not. Fine, what does that mean? Ford is already going with Volvo & Mazda based platforms, so the mechanicals are becoming sophisticated. It's more about appearance, packaging, & marketing. Ford is either entry-level or performance. Mercury will offer more on the one hand and less on the other. How about some cliches?

You won't expect to find a Mercury at KMart or the dragstrip. Not saying you won't find them there - just not expect to. That's perhaps the key to Mercury's marketing - expectations. Ford is apple pie; Lincoln is ala mode or covered in whipped cream; Mercury is something with chocolate (hmmm... many women say they love chocolate...) - or - is for people who don't eat dessert.. Again, hmmm... Mercury could be for all those people who have a gym membership because they don't get a workout as part of their jobs. Lincoln can be for people who neither have physically demanding jobs nor use gym memberships. Will Mercury buyers switch to Lincoln about the time they stop using those gym memberships? Is the theme becoming apparent?

Ford people may be expected to (occasionally) listen to country western. Mercury owners may (occasionally) listen to classical music - or perhaps alternative rock? Alternative is an important word for Mercury, and probably more appropriate than 'urban', tho 'urbane' might work. 'Wannabe' might also. But there's nothing wrong with 'becoming what you want to be', ie. achieving your goals. It all depends on your interpretation. Coffee in your thermos? Or coffee at Starbucks? Can Mercury pull a Starbucks? Well, from their recent efforts, it seems that Mercury has finally turned "just a bit nicer than Ford" into a meaningful-to-the-customer design and marketing philosophy. Time will tell how the car-buyers interpret it and if it's a popular philosophy.