The long-awaited, much-discussed BMW X7 finally enters the home stretch. Barely four months away from the start of production, BMW brought six early X7 prototypes to the Spartanburg, South Carolina, plant that will build the new crossover, and invited a small group to sample the driving dynamics. Munich’s other full-sized SUV hopes to prove itself the lively, luxurious, and laudable answer to the question, “What took so long?”

Company engineers said their two priorities were to avoid simply building a larger X5, and to ensure the husky X7 performed like a BMW. The short answer is that they succeeded on both counts. The slightly longer answer is that they might have scored better on the second count than on the first.

Perhaps it was the optic-distorting effects of camouflage, but the X7 did not look flagrantly larger than the X5. It wasn’t until the X5 camera car sidled up to one of the X7 testers on the highway that the slight difference in bulk became apparent, at least from the rear. BMW didn’t want to get into specific dimensions; all an engineer would tell us is that the X5 is less than five meters (4.91 to be exact, or roughly 16 feet) whereas the X7 stretches beyond five meters.

Not only does the X7 sit on a longer wheelbase than the X5, the X7’s body’s been skewed rearward. Comparing the X7 to the current X5, the rear overhangs are proportionally similar, but there’s barely any sheetmetal ahead of the X7’s front wheels. Every X7 comes with a third row, so the sliding adjustment carves out as much practical room possible for those two extra chairs.

The third row provided perfectly serviceable contingency seating for an adults-only posse — a day out for polo and dinner won’t cause arguments over which pair gets sent to the back of the X7 class. We had an inch or so of extra headroom, and the bench and second-row captain’s chairs were unexpectedly more accommodating to boots.

The X7s we drove fly around the world for testing and final tuning before production begins in August. Expect an unveil either at the Frankfurt Motor Show or, more likely, the L.A, Auto Show. Then the X7 arrives at dealers in the first quarter of next year as a 2019 model. After that — unless BMW somehow cocks things up terribly in the next six months — you can expect to see a ton of X7s on the streets.