A new RS6 costs about $83,000, and this powertrain upgrade costs $29,500 for the kit; labor, Hoppen says, should be between $3,000 and $5,500, depending on the shop.

From some angles it can seem like a busy concoction of shapes, but from the side in particular it almost has the proportions of a Hot Wheels car, particularly on the larger 22-inch alloy wheel option.

The Audi RS6 Avant is the most traditional car of the group. Remove the badges, pick a more subtle color and the standard 20-inch wheels, and it could be mistaken for an A6 wagon, making it quite ...