Correction: An earlier version of this column incorrectly identified Interstate 81 as Interstate 80. It has been updated.

(Photo courtesy of Audi)

My MOI (moment of insight) was out to lunch. It happens. When it happens, I have nothing to do except relax until it comes back.

I relax by driving, preferably along westbound Interstate 66 and southbound Interstate 81 in and through Virginia’s Shenandoah Valley. They are beautiful stretches of road, especially in the early spring in a fine automobile.

I was driving the 2012 Audi A3 2.0 TDI Premium wagon. It is an easy, diesel-powered front-wheel-drive runner — a great introduction to Audi’s suite of luxury cars.

Then it hit me: Knowledge has a way of ruining pleasure. You can have a good time drinking Sunday night. But you know that too many drinks will ruin Monday morning. You can gobble shrimp and crayfish if you don’t mind paying the sometimes painful penalty of an iodine allergy.

Knowledge tempers emotion and action. I was driving along I-66 marveling over how well the A3 2.0 TDI handled, even in crosswinds — so wonderfully stable! It danced around curves in Shenandoah National Park and performed wonderfully well until I reached the Hightop Mountain area of Skyline Drive, 3,637 feet above sea level, where the car began wheezing.

(Photo courtesy of Volkswagen)

I didn’t mind that. Skyline Drive isn’t my daily route for anything. Besides, it was such an nice little wagon/hatchback overall. But I began suffering buyer’s remorse without ever having bought the thing.

The premium version of the A3 2.0 TDI starts at $30,250. That’s a lot of money for what essentially is a small family hauler. That it has exactly the same engine as the Volkswagen Jetta SportWagen TDI, which starts at $25,540, dampened my enthusiasm for the Audi A3 wagon even more.

Both wagons have a 2-liter, in-line turbocharged four-cylinder, diesel engine (140 horsepower, 236 foot-pounds of torque) as standard equipment. Both have standard front-wheel drive. The Audi sends power to those wheels via a standard six-speed “automated manual” transmission — one that can be used automatically or manually. The Volkswagen does it through a standard six-speed manual gearbox, with an automated manual available as optional equipment.

Both wagons offer an average 30 miles per gallon in the city and 42 on the highway.

From the rear, the A3 2.0 TDI wagon and the Volkswagen Sportwagen TDI look pretty much the same, distinguishable primarily by the “VW” logo on the rear of the SportWagen TDI and the four interlinked, Olympic-like circles on the back of the A3 2.0 TDI.

The front ends of the two wagons are quite different. The SportWagen TDI has an attractive double-slat end-to-end grille punctuated by a circled “VW” logo in the middle. The grille flows nicely into headlamps right and left. The whole VW front package looks better than that of the A3 2.0 TDI with its pompous (for a car so small) wide-mouthed reverse-horseshoe grille — which has a horizontal band across it beneath the interlinked Audi circles, as if to suggest “not really Audi.”

But the A3 2.0 TDI is an Audi. It is just an Audi that does not need to be.

Audi is Volkswagen’s luxury group. It should be Volkswagen’s luxury group without having an entry-level luxury anything. But it is trying to remain competitive in a global automotive game of marketing foolishness.

Car companies worldwide are trying to capture buyers at every income segment possible. General Motors, Ford and Chrysler long have been among the most able practitioners of the artifice of dolling up what are offered as affordable economy cars in one segment to be sold as more expensive entry-level luxury cars in another. But the U.S.-based car companies are by no means alone. You like the Porsche Cayenne? You can get it for less as the Volkswagen Touareg. Before you spend money on the Chrysler Town & Country minivan, which starts at $29,995, you might want to check out the practically identical (including the same 3.6-liter V-6 engine) Volkswagen Routan minivan, which starts at $27,020.

I enjoyed my time in the Audi A3 2.0 TDI. Other than its asthmatic behavior at mountain elevations, there was little to complain about. But I finished my round-trip journey into the Shenandoah Valley with a profound moment of insight. Four thousand dollars could get Mary Anne, my wife, the tile she wants in the new downstairs bathroom. It could pay taxes. It could buy a lot of things. Had I a choice between the 2012 Audi A3 2.0 TDI and its equally capable, less-expensive Volkswagen counterpart, the 2012 SportWagen TDI, I’d buy the Volkswagen.