What's the difference between a car you love and car you can't live without?

Answer: 30 horsepower and 22 lb-ft.

Such is the case for the Volkswagen Passat TDI and me. If you missed the comparison test last month, Vee-Dub's fresh oil-burner outclassed two of the segment's newest gas-electrics, the Toyota Camry Hybrid and the Hyundai Sonata Hybrid. Further, the TDI's siblings, the Passat 2.5 and VR6, beat their respective Camry and Sonata foes as well, making it a clean sweep for Chattanooga's hottest export. And let's just say the Passat had a decent finish in this issue's Car of the Year contest.

Here's why I love the TDI: 236 lb-ft of torque, a cruising range of almost 800 miles, up to 35 mpg combined, a huge 15.9-cubic-foot trunk, an A6-size interior (and then some), and your choice of a six-speed manual (should you love the connectedness of a stickshift) or a six-speed twin-clutch auto (should you not). For those seeking a high-performance family sedan -- in terms of mpg and lateral g--the Passat TDI is unbeatable.

But it's not a car I can't live without. At least not yet. It needs 8.7 seconds to scoot from 0 to 60 mph, which is satisfyingly quick but quite a bit slower than the Camry Hybrid, at 7.2. While I love the TDI, and would still take one over the Toyota, I could live without it, given that the Camry's extra oomph would be enough to quell my heartache. No, for me to comprehend life without the TDI as completely unacceptable would require a simple fix. In fact, engine displacement, peak rpm levels, and transmissions could all stay the same, the only differences being 30 extra hp and 22 more lb-ft.

In Europe, Volkswagen offers the Passat with a choice of two 2.0-liter diesels: the one we get, with 140 hp at 4200 rpm and 236 lb-ft of torque at 1750 rpm, and another whose higher boost and modified internals create 170 hp at 4200 and 258 lb-ft at 1750. VW estimates the Euro Passat's 0-to-62-mph time drops 1.2 seconds when opting for 170 over 140. The U.S. Passat is bigger and heavier than the Euro version, so figure about a second difference, or roughly 7.7 seconds to hit the big 6-0. Better still, with 22 additional lb-ft on tap, a 170-horse U.S. TDI would launch even more energetically from stoplights and out of turns, two feats it already does exceptionally well with "just" 236 lb-ft. And did I mention fuel economy between the Euro Passat's two 2.0s, per the European cycle's combined rating, is the same with the manual and only 1 mpg worse with the 170-hp/DSG?

So why doesn't Volkswagen bring over the more potent TDI? I posed this question to VW's PR crew and was told it's under consideration, and, more important, doable in terms of meeting U.S. emissions. Their take: In light of the current 2.0's prodigious 236 lb-ft, the upscale 2.0's extra 22 lb-ft (and 30 horses) aren't entirely necessary. I don't disagree with them, but just because it's not necessary doesn't mean it's not the right move.