BMW
X4 M
BMW
X6 M
BMW X4 M vs BMW X6 M: 2023 Comparison
The short answer
The BMW X4 M offers fuel economy, while the BMW X6 M excels at power instead. Choose the BMW X4 M if you prioritize fuel economy in daily driving, or the BMW X6 M if power matters more for your needs. Both are covered by real owner reports on CarWizz.
Specs side by side
What owners say
X4 M
Overall
Mixed sentiment with a clear distinction between the high-performance M model and the standard X4. The X4 M is described as an "entirely different car" from non-M models, offering a substantial jump in power and performance that owners find compelling. The B58 and previous N55 inline-six turbo engines in the M40i and M models are frequently praised for being "dead reliable" and "a monster of a motor." However, significant and recurrent criticisms focus on punitive maintenance costs as the vehicle ages, poor rear visibility and compromised cargo space due to the coupe design, and persistent issues with tire wear and alignment on vehicles equipped with large wheels and sport suspensions.
Best version to buy
Insufficient owner data available to declare a consensus "best" version. However, there is a strong, recurrent opinion that the full "M" model (e.g., X4 M Competition) is worth the significant price premium over the M Performance model (X4 M40i), described as an "entirely different car" with different interior materials and a substantially more powerful driving experience.
Known issues
- ⚠High maintenance and repair costs: described as "punitive" and becoming very expensive after approximately 60,000 miles, with dealership service charges frequently cited as high. Frequency: very frequent.
- ⚠Excessive and uneven tire wear: particularly on front tires with outer edge wear, noted on vehicles with 20" wheels and sport suspensions, often requiring replacement as early as 15,000 miles. Frequency: recurrent.
- ⚠Alignment difficulties and pulling: issues with pulling to one side, especially in winter conditions, with some reports of non-dealer shops being unable to properly diagnose or correct the alignment. Frequency: recurrent.
X6 M
Overall
Mixed sentiment with a clear divide between ownership phases. The vehicle is universally praised for its immense performance, handling that defies its SUV classification, and the special, hand-built nature of its S63 engine. Long-term owner reports describe it as a highly capable and enjoyable daily driver that can handle imperfect roads and conditions while delivering sports car-like dynamics.
Best version to buy
The full X6 M is strongly recommended over the non-M X6 models (e.g., xDrive40i, M50i/M60i) for several reasons. The hand-built S63 engine in the M is reported to be more reliable than the standard N63 twin-turbo V8 found in non-M models, which is notorious for oil consumption and injector issues.
Known issues
- ⚠Catastrophic drivetrain failures: includes repeated "Drivetrain" warning messages accompanied by a complete loss of power, requiring the vehicle to be towed. One owner reported 14 separate incidents within two years.
- ⚠Engine (S63/N63) reliability concerns: issues include failing fuel injectors (often requiring replacement of all eight), excessive oil consumption, and potential for severe cylinder wall wear.
- ⚠High repair and maintenance costs: parts like laser headlights are cited as costing over $6,000 USD each. Brakes are expensive but long-lasting. General service costs are high. Frequency: very frequent.
The verdict
The BMW X4 M is the better choice for most buyers.
It has better fuel economy on its best-equipped version than the BMW X6 M, based on the data above. If power matters more to you than running costs, the BMW X6 M is worth a closer look instead.
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Frequently asked questions
Which is more reliable, the BMW X4 M or the BMW X6 M?
Owner reports show similar reliability sentiment for the BMW X4 M and the BMW X6 M. Check the known issues listed above for specific differences between the two.
Which is better for families, the BMW X4 M or the BMW X6 M?
Data on family-specific factors like cargo space is limited for one or both models, but based on available reports, both are positioned as practical daily drivers. Check the specs table above for seating and body type.
Which has better fuel economy, the BMW X4 M or the BMW X6 M?
The BMW X4 M is more fuel-efficient on paper: 10.7-10.8 L/100km combined versus 12.7-12.9 L/100km for the BMW X6 M, based on the best-equipped catalogued version of each.
Which is cheaper to maintain, the BMW X4 M or the BMW X6 M?
Exact maintenance costs aren't in our data, but owner reports mention cost-related concerns more often for the BMW X6 M than the BMW X4 M. See the known issues comparison above.