Tasty margins and a willing audience make full-size luxury SUVs a cutthroat business. And we don't mean it in the "friendly afternoon soccer game way," either. Think Michael Douglas in "Wall Street."

Cadillac is offering $5,000 to Lincoln owners willing to trade allegiances. The kicker? Trade in your 1999 or newer Lincoln Navigator for a new Cadillac Escalade. Why now? The new Navigator is nearing dealer lots and General Motors would love to take wind out of its sails.

Bloomberg reported Tuesday that the incentive is part of a concerted effort to keep GM's market share in an effort to stem a surge from Ford. In addition to a new Lincoln Navigator, a new Ford Expedition (mechanically related to the Navigator) is heading toward dealers' lots soon, and will compete better against the Chevy Suburban/Tahoe and GMC Yukon/Yukon XL lineup that has dominated the market since the Expedition was last redesigned.

The Escalade has a tastier profit margin, however, and at nearly $74,000 to start, it will need some help moving off the lots in the face of a new Navigator that undercuts it by a couple thousand dollars. Cadillac's offer can be combined with other offers from GM, so that incentive can climb further.

The Escalade is saddled with a tried-and-true, thirsty V-8. The Navigator gets a newfangled turbocharged V-6.

Call it the luxo-Hatfields and McCoys for the 21st century. It's just, this time, one of them has $5,000 on the hood.