The 325 horses emanate from the 4.4-liter DOHC 32-valve V-8 and are routed rearward via a ZF Type G six-speed manual, a ZF 6 HP 26 six-speed automatic, or BMW's sequential manual gearbox (SMG), a no-clutch-pedal six-speed with paddle-operated shifting.

The suspension is straight 5-series: a strut braced by two spindly aluminum links in front and beefy cast-aluminum lower control arms in back assisted by a pair of lateral links on each side, all mounted to a tubular aluminum crossmember. BMW loves its steel coils; air springs, variable-rate shocks, and other suspension electrotrickery are for others. The 645's one optional undercarriage fandangle is front and rear hydraulic variable-rate anti-roll bars that help keep the body flat in corners.

Inside, the plastic, metal, and leather converge in lush geometric shapes set in organic sweeps of curves and humps. Above it all rises the iDrive's cycloptic TV eye, always ready to snare your attention with dancing cursors, multicolor pictographs, and endless control menus.

Coupes die or thrive by their styling, and the 645Ci is yet another complex BMW shape that is more cerebral than emotional. The cab-backward body is the off-the-steroids production version of the gull-wing Z9 GT concept car from the 1999 Frankfurt auto show. Family ties to the big 745i sedan lurk in the oversize grille kidneys, the smoothly groomed flanks, the single thin swage line along the side, and the boxy trunklid. The latter juts out from the deep 13-cubic-foot trunk like the Rock of Gibraltar, which is not far from the southern Spanish town of Málaga, where the 645 was unveiled to automotive writers.

This one screaming feature is set amid fascinating details all but invisible in print. For example, the border between the hood and front fenders is a complicated sculpture of inward and outward creases that slash down the nose to define the glowering headlights. The side character line starts on the thermoplastic front fender, streaks across the aluminum door skin, and fades away into the steel rear quarter-panel, all the while maintaining perfect shape uniformity despite three completely diverse materials.