Put that power on a track, and you’re going to see some big speeds, though it’s hard to believe them. You’re well isolated in the cabin, divorced from the sensation of speed, and quickly find yourself going much faster than you expected. This is a monster of an I-6, absolutely charging to redline without slowing down. M engineers say they’ve done a ton of work optimizing the twin intake tracts, and it shows in the seeming absence of turbo lag and stout midrange torque. Pooh-pooh the eight-speed automatic’s torque converter all you want, but it shifts more than quickly enough for track work.
Really making things happen, though, is that active rear differential. There’s no way you won’t feel it working as you flatten the throttle on your way out of a corner. It wants to rotate the car, and the only thing holding it back is the stability control computer. In M Dynamic mode, it’ll give you just a taste of oversteer under power to rotate the car, and the nice BMW people assure me if you turn the computer off this thing will drift real good. They also requested I not do that.
Of course, physics has its limits, and a high center of gravity and hefty curb weight mean you can only do so much. The big anti-roll bars and active dampers keep the body pretty flat, but there’s a lot of weight moving around under you. The brakes do an even better job, refusing to fade under moderately hard hot laps despite the weight. Less impressive is the electrically assisted power steering, which is accurate and precise but fairly lifeless for an M vehicle. Business up front and a party in the back, just like those mullets the Alabama boys were rocking back in the
For that other 100 percent of the time you’re not tracking your SUV, the X3 M and X4 M are private jets with afterburners. Pro tip from someone who used to work on them: Most private jets aren’t especially fancy, just expensive. Only the biggest ones are flying presidential suites. The X3 M and X4 M are still X3s and X4s at their core, in the middle of the BMW SUV size and luxury hierarchy. The interiors get carbon-fiber trim and annoying shifters that emulate BMW’s obnoxious dual-clutch shifter, plus color inserts in the seats. It’s all perfectly nice, but there’s no doubt your $70,895 (X3 M) or $74,395 (X4 M) is going to performance parts, and if you want all the ponies, it’s $77,895 (X3 M Competition) or $81,395 (X4 M Competition).
Get on a real road, and the X3 M and X4 M are stonking fast and still isolated. The adaptive dampers are the real heroes here, giving them a moderately firm but never harsh ride in Comfort setting. Few vehicles that can do these track times are this pleasant to drive to and from the track. Meanwhile, that same separation from the world around you that lets your speed sneak up on you at the track is all the more effective on the street. You and every car around you on the interstate can be doing 90 mph, and you’ll still feel like everyone else is driving too slow.
You’ll pay for it, though. Regardless of which model you pick, you won’t get better than 14/19/16 mpg city/highway/combined, and you better believe it’s premium gas only in these puppies.
It’s the money that’s the real kicker here. If you’re in a hurry and need to hit 60 mph in under 4 seconds, then I guess you need an X3 M or X4 M. If you can spare an extra second, an X3 M40i will do it in 4.8 seconds, starts at $55,645, and gets 20/27/34 mpg city/highway/combined. But hey, it’s your 15 grand plus gas to spend.