SAN FRANCISCO – Strike “turbo lag” from the automotive lexicon.

The well-worn caveat is to turbocharging what dizziness is to Viagra – an unfortunate side effect.

But now, thanks to BMW AG’s ’07 335i coupe, the term is as dead as Latin.

The sleek ride features BMW’s first blown engine since the 745i’s 3.2L 6-cyl. mill made its mark in 1981. The new coupe’s 3.0L DOHC I-6 generates 300 hp and 300 lb.-ft. (407 Nm) of peak torque, courtesy of its turbo module from Mitsubishi Heavy Industries Ltd.

This setup makes a great car even better. Provided, of course, it is not equipped with the optional 6-speed Steptronic gearbox.

BMW claims its manual-mode shifts are 50% quicker, but this balky system is disturbingly similar to the M5’s quirky sequential manual gearbox. Intoxicating power lies waiting under your right foot, but instead you must cool your heels while the “pre-selected” gears synch up.

On the clock, the delays are just fractions of a second. But it’s long enough to yearn, endlessly it seems, for a clutch pedal.

Compounding this frustration is the knowledge the 335i’s twin turbos are designed to mitigate spool-up time, the condition responsible for that derisive “lag” label. Each turbo serves three cylinders and, with a relatively modest boost pressure of just 8.7 psi (0.6 bar) per unit, they spool up quickly.

Factor in the explosive pairing of BMW’s high-precision direct-injection system and piezo-hydraulic fuel injectors, and the 335i becomes a shameful tease.

Mercifully, there is no waiting when the car is outfitted with the 6-speed manual transmission. This package delivers authoritatively, without turbo whine.

However, there may be some whining at stoplights if, say, a Mustang GT owner pulls up beside the 335i. Ford’s sporty flagship has long enjoyed exclusive domain over exhaust-note excellence, but the 335i’s I-6 is so burbly, pony car aficionados will blush.

Mounted on a frame that is 25% stiffer than its sedan cousin, the car is superbly balanced, an attribute borne out by its variable-speed, power-assist steering system. It tracks true, and its electronic stability control system keeps you honest without spoiling the fun.

The front fenders are lightweight plastic, but they hardly compromise the car’s look. Lean and muscular, its long hood, dramatic roofline and short, taut rear end suggest the appearance of some dangerous beastie coiled and ready to strike.

Tipping the scales at a relatively trim 3,571 lbs. (1,620 kg), the 335i benefits from an aggressive lightweight strategy that includes aluminum-intensive suspension and engine components.

Inside, the gauge clusters are sufficiently sporty. And while the brushed aluminum dash may be the knee-jerk choice, in keeping with the car’s high-performance pedigree, BMW offers a suitably bold alternative in striking gray poplar.

A nifty feature is an automatic seatbelt presenter for the front passenger seat. Sensors indicate when the seat is occupied, triggering the extension of a plastic arm carrying the shoulder harness.

Though handy, repeated use by broad-shouldered passengers portend disaster for the flimsy apparatus. And as with the Steptronic gearbox, patience is required before the full benefit is realized.

Thoughtful pauses seem a consistent theme for the 335i, with a starting price of $41,295.

After all, it rolls out a year after the sedan version of BMW’s fifth-generation 3-Series.

But in the end, it is worth the wait.

emayne@wardsauto.com