Two BMW diesel vehicles, the 335d sedan and the X5 xDrive35d crossover, are now qualified for the federal “Advanced Lean Burn Technology Motor Vehicle Tax Credit.” Buyers of the 335d will be eligible for up to $900 in tax credits, while those purchasing the X5 can qualify for as much as $1,800 from the IRS.

Federal tax credits were previously granted to clean diesel vehicles from Mercedes and Volkswagen.

The credits will offset some of the premium associated with purchasing the pricey BMW clean diesels, and will alter the economic calculation for buying the diesel rather than the conventional gasoline versions of the vehicles.

BMW 335d

The 335d costs $44,750 and has fuel economy ratings of 23 city/36 highway. Compare that to the gasoline-powered 335i’s $41,125 sticker, and 17 city/26 highway rating. The $3,625 difference is somewhat offset by a $900 tax credit.

BMW X5 xDrive35d

The X5 xDrive35d starts at $52,950 and gives 19 city/26 highway, while the base gas-powered X5 costs $48,325 and has fuel economy ratings of 15 city/21 highway. The $4,625 difference is reduced by a $1,800 tax credit.

When factoring in the tax credit with price, mileage, and cost of fuel, the gas-powered Bimmer beats out the clean diesel on economics—but not by much. Also, as with hybrids, economics are only part of the buying equation. Reduced oil consumption, cleaner tailpipe emissions, and a longer cruising range—up to 40 percent longer—are also factors for a growing number of car buyers.