BMW inline sixes have always been something special - and nobody knows that more than BMW. The company has offered decent 4-cyl. engines for those who craved a BMW and had to do it on a budget. But BMW made customers lay out more serious cash for the privilege of possessing one of its exhilarating 6-cyl. engines.

That brings us to this year's new 2.5L DOHC I-6. Proving that even BMW acknowledges how intensely competitive the U.S. car market has become, the company is fitting the 2.5L six as the "base" engine in the 1998 323is and 323i convertible - yet in those cars the six costs less (when representatively equipped) than the same cars with last year's 4-banger base engine. In fact, BMW says the 1998 323is is the first 6-cyl. BMW priced under 30 grand in five years.

With its deliberately obtuse nomenclature for the new models, however, BMW forces an explanation. Typically, you know the engine size (and model) for any given BMW by the numeric designation; a 325is, for example, is a 3-Series with a 2.5L engine (never mind about the i and the s).

You can't depend on anything these days. The new 323 models actually are motivated by a new 2.5L I-6. Wait, you say: BMW gave us a 2.5L inline six for years. Yeah, but this one's not the old 2.5L from the M50 engine range; the current 2.5L is based on the M52 engine family of the current 2.8L inline six (which by the way is still offered as the upgrade engine for all 3-Series except the M3).

The old M50-based 2.5L finished its life delivering 189 hp, while BMW says the new unit develops 168 hp. We say BMW has conservative dynamometers, because the new 2.5L I-6 feels fully as strong as any BMW we recall with the old engine, and we think almost any driver would be pressed to tell the difference between the 168-horse 2.5L and the 2.8L six that develops 190 hp. What's more, the 2.5L's 181 ft.-lbs. (245 Nm) of torque augurs in with such a wallop, and over such a wide rpm range, that the 2.8L seems strangely superfluous.

All the good stuff from the big-brother inline is here in this de-stroked version of the 2.8L, including variable valve timing and the sweetest mechanical engine snarl in the business.

Uncanny smoothness and refinement are assumed from any BMW inline 6-cyl.; combined with the 2.5L's peerless power delivery and the tempting new price structure, no other luxury/sport 6-cyl. engine comes close.