Honda’s Accord has grown substantially in most dimensions for 2008… so much so that certain models have achieved full-size status under EPA guidelines. And while the automaker has been keen to set their latest family sedan toe-to-toe with the Toyota Camry and Nissan Altima, it has been understandably shying away from one less-than-flattering in-house competitor—the Acura RL.

Allow us to explain. Acura’s slow-selling luxury flagship has never really found its footing in the marketplace, and while it isn’t actually in the same class, Honda’s new Accord is actually nearly as powerful as the premium-branded range topper. What’s more, it’s also larger inside and out.

Using Honda’s own specifications, a quick comparison finds that the RL and Accord share the same 110.2-inch wheelbases and 72.7-inch widths, but the Accord is actually longer (194.3 vs. 193.6) and taller (58.1 vs. 57.1). It also has a substantial weight advantage, tipping the scales at 3616 pounds—with navigation—vs. 4014 pounds.

In terms of power, the two share the same engine displacement and configuration (3.5-liter V-6), but the Acura’s 290 horsepower and 256 pound-feet of torque shade the Accord’s 268 hp and 248 lb-ft. Of course, the Acura has more weight to tote around (thanks largely to its more complex all-wheel drive system), and it also requires premium fuel, while the Accord V-6 is happy running on 87 octane.

Inside, the tale of the tape is eerily similar as well. The Accord has more front head room (39.0-inches vs. 38.5), identical rear head room (37.2), and more leg room front and rear (42.5 and 37.2 vs. 42.4 and 36.3, respectively). The Accord is better in most shoulder- and hip-room categories, too. It even offers more cubes in the trunk (14 cubic feet vs. 13.1).

Not to keep kicking the RL while it’s down, but the Accord also offers substantially better fuel economy (21/31 vs. 16/24), a tighter turning circle, and so on.

What’s most telling, however, is the pricing gulf between the two models. A bog-standard RL carries an MSRP of $46,280, while an Accord V-6 with navigation runs $28,060. That’s a difference of $18,220, or enough money to buy a Fit Sport with a boatload of options.

All of this isn’t to say that the RL is a bad car—it isn’t. But as a value proposition, an already tough sell for Acura dealers has just gotten even more difficult.