Many regard the third-generation BMW 7 Series, codenamed E38, as the best 7 Series. It's hard to disagree with that. The combination of simple and straightforward exterior lines delivers classiness and sportiness. We don't think we'd be out of line to name the E38 as one of the most beautiful sedans ever built. Equally important is that it was the last analog 7 Series; its E65 successor debuted the iDrive infotainment system (and the "Bangle-Butt," which is another conversation). There are plenty of used E38s still out there, but none are as perfect as this one.

Up for sale on Cars And Bids is this final model year 2001 740i short-wheelbase BMW equipped with the M Sport Package. It has been repainted in a stunning Estoril Blue; it was originally Titanium Silver. But that's not the best part about it.

Under the hood is the 4.9-liter S62 V8 from a 2003 E39 M5, which was totaled in an accident. Fortunately, its six-speed manual was salvaged too. Total output is rated at 394 horsepower and 369 lb-ft of torque, all of which is sent to the rear wheels. The rest of the car is also a mix and match of parts.

For example, the brakes are taken from a 750iL and the steering wheel, instrument cluster, leather sun visors, and limited-slip differential all come from the crashed E39 M5. Also notice the Alpina front bumper and AC Schnitzer wheels. Some of its original equipment includes Xenon headlights, a sunroof, heated front seats, a Mark IV navigation system, and dynamic stability control.

At the time of the engine swap, the chassis had 169,000 miles but the old-new engine had about 116,900 miles; the swapped instrument cluster shows the latter figure. Because of this discrepancy, the listing says "true mileage unknown." The exterior is generally in good shape but there is some cracking on the window seals, a few wheel scratches, wear and tear on the driver's seat, and a few trunk carpet stains.

As of this writing, the highest bid reached $17,000 and the auction ends on May 5. The seller notes they're the ones who performed the engine swap and it's the seventh such swap they've done.