BMW
X3 M
BMW
X4 M
BMW X3 M vs BMW X4 M: 2021 Comparison
The short answer
Based on available data, the BMW X4 M comes out ahead of the BMW X3 M on fuel economy. Check the specs table and owner sentiment below for the full comparison before deciding between the two. Both are covered by real owner reports on CarWizz.
Specs side by side
What owners say
X3 M
Overall
Owner sentiment is sharply divided, heavily dependent on the specific powertrain and ownership expectations. The high-performance X3 M and X3 M Competition models are praised for their exceptional power, engaging driving dynamics, and status as a practical yet thrilling performance SUV. However, this enthusiasm is tempered by very frequent and severe criticism regarding long-term reliability, exorbitant maintenance and repair costs outside of warranty, and significant depreciation.
Best version to buy
X3 M40i: This model is specifically recommended over the full X3 M for daily driving, striking a better balance between performance, comfort, and cost. It is described as offering ample power and a fun driving experience without the extreme harshness and running costs associated with the full M models.
Known issues
- ⚠Catastrophic engine failures (timing chain guide disintegration on N20 engines around 150,000 miles / 241,000 km): very frequent.
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.
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 X3 M, based on the data above. If power matters more to you than running costs, the BMW X3 M is worth a closer look instead.
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Frequently asked questions
Which is more reliable, the BMW X3 M or the BMW X4 M?
Owner reports show similar reliability sentiment for the BMW X3 M and the BMW X4 M. Check the known issues listed above for specific differences between the two.
Which is better for families, the BMW X3 M or the BMW X4 M?
Both seat a similar number of passengers based on our data. The BMW X3 M is classed as a SAV, the BMW X4 M as a SAC, which affects cargo space and ride height for family use.
Which has better fuel economy, the BMW X3 M or the BMW X4 M?
The BMW X4 M is more fuel-efficient on paper: 10.7-10.8 L/100km combined versus 10.8-11 L/100km for the BMW X3 M, based on the best-equipped catalogued version of each.
Which is cheaper to maintain, the BMW X3 M or the BMW X4 M?
Exact maintenance costs aren't in our data, but owner reports mention cost-related concerns more often for the BMW X3 M than the BMW X4 M. See the known issues comparison above.