BMW 3 Series trim comparison
2026 BMW 3 Series M340i vs M3
The 3 Series M340i starts at $62,300 while the M3 is $79,300. That $17,000 gap buys 6 meaningful differences.
This trim jump changes the engine from 3.0L I6 mild-hybrid Turbo to 3.0L I6 Turbo. Everything else is secondary to whether that powertrain difference matters for how you drive.
Start with the M340i if the 3.0L I6 mild-hybrid Turbo already feels sufficient for the way you drive. Step up to the M3 only when the 3.0L I6 Turbo powertrain is the reason you are moving higher in the lineup.
If you are budgeting this move monthly, the jump from the M340i to the M3 is about $299/month on a 60-month loan at 6.5% APR with 10% down. That works out to roughly $17,940 more by the time interest is counted. The payment only makes sense if that different powertrain matters to the way you actually drive, tow, or live with the vehicle.
Lock one trim, change the other side, and move through exact pair pages without resetting back to the full lineup every time.
Who notices the difference
The higher trim starts to make more sense when you are specifically shopping for the stronger powertrain, not just more trim content.
When both feel the same
Same platform and drivetrain options on both trims.
The upgrade math
You are paying $17,000 for 5 measurable differences, which works out to about $3,400 per change.
Key Differences at a Glance
This is the fast read: price, power, efficiency, and the feature flips most likely to change the answer.
Every Difference, Side by Side
This is the full read behind the quick decision signals above: the complete hardware, comfort, and equipment story. 6 specification differences, 1 shared.
Full Specification Comparison
Specifications reflect available data as of early 2026. Confirm details with an authorized dealer before purchasing.
| Spec | M340i | M3 |
|---|---|---|
| Pricing | ||
| MSRP | $62,300 | $79,300 |
| Powertrain | ||
| Engine | 3.0L I6 mild-hybrid Turbo | 3.0L I6 Turbo |
| Horsepower | 386 hp | 473 hp |
| Torque | 398 lb-ft | 406 lb-ft |
| Transmission | 8-speed shiftable automatic | 6-speed manual |
| Drivetrain | RWD | RWD |
| Fuel Economy | ||
| City MPG | 27 | 16 |
| Highway MPG | 33 | 23 |
| Combined MPG | 29 | 19 |
| Fuel Tank | 15.6 gal | 15.6 gal |
| Annual Fuel Cost (EPA) | $2,000/yr | No published data |
| Dimensions | ||
| Curb Weight | 3,896 lbs | 3,840 lbs |
| Wheelbase | 112.2" | 112.5" |
| Length | 185.9" | 189.1" |
| Width | 71.9" | 74.3" |
| Height | 56.4" | 56.6" |
| Safety | ||
| NHTSA Overall | 5/5 stars | 5/5 stars |
| Warranty | ||
| Bumper-to-Bumper | 4yr/50k | 4yr/50k |
| Powertrain | 4yr/50k | 4yr/50k |
| Corrosion | 12yr/unlimited | 12yr/unlimited |
| Roadside Assistance | 4yr/unlimited | 4yr/unlimited |
Data sources: licensed third-party automotive data, EPA fueleconomy.gov, NHTSA, and official manufacturer materials. Values marked est. are estimated.
2026 BMW 3 Series M340i vs M3 Questions Shoppers Ask
Use this page for the direct trim answer, then zoom back out to the BMW 3 Series lineup, the BMW brand hub, the Compact Cars, the how to pick a trim guide, or our mid-trim value research when you need the bigger shopping path behind this one matchup.
How much more does the 2026 3 Series M3 cost than the M340i?
The M3 starts at $79,300 compared to $62,300 for the M340i. That is a $17,000 difference, or approximately $299/month more on a 60-month loan.
Do the 2026 BMW 3 Series M340i and M3 have the same engine?
No. The M340i uses a 3.0L I6 mild-hybrid Turbo (386 hp, 398 lb-ft), while the M3 has the 3.0L I6 Turbo (473 hp, 406 lb-ft). That is 87 more horsepower. Both pair with the same 8-speed shiftable automatic.
Do the 2026 3 Series M340i and M3 have the same drivetrain?
Yes. Both come with RWD as standard. The differences between these trims are in features and equipment, not drivetrain.
Is the 2026 3 Series M340i or M3 safer?
Both share the same BMW 3 Series platform with an overall 5-star NHTSA safety rating. Safety ratings are model-level and identical across trims. The trim choice affects comfort and features, not crash protection.
What warranty does the 2026 BMW 3 Series come with?
All 2026 BMW 3 Series trims, including both the M340i and M3, come with BMW's standard warranty: 4yr/50k bumper-to-bumper and 4yr/50k powertrain coverage. Warranty does not vary by trim level.
Is the 2026 BMW 3 Series M3 worth $17,000 more than the M340i?
The $17,000 buys the 3.0L I6 Turbo. If that powertrain matters for how you drive, yes. If not, the M340i does the same job for less.
Which 2026 BMW 3 Series trim gets better fuel economy, the M340i or the M3?
The M340i is the more efficient of the two at 29 combined MPG, versus 19 for the other trim. That matters most if you are balancing running costs against the extra power, drivetrain, or comfort equipment tied to the pricier trim.
The Full Story Behind This Price Gap
Use the direct answer above for this exact matchup, then use these guides to understand whether you are really looking at a feature step-up, a package shuffle, or the point where the lineup starts changing in a meaningful way.
What $17,000 Gets You
The 3 Series M3 costs $17,000 more than the M340i. Whether that is worth it depends on how much you value the 3.0L I6 Turbo engine (+87 hp). Power and comfort matter differently to different buyers. Weigh them against your priorities.
M340i vs. M3: Day-to-Day
The M3 comes with the 3.0L I6 Turbo instead of the M340i's 3.0L I6 mild-hybrid Turbo. That means 87 more horsepower and 8 more lb-ft of torque. That extra power shows up most clearly once you are out of town and asking more of the drivetrain. The cost of that extra capability is roughly 10 fewer combined MPG.
Fuel Economy Comparison
The 3 Series M340i gets 10 more combined MPG. At $3.50/gallon and 12,000 miles/year, that saves roughly $763 per year or $3,815 over five years of ownership.
Summary
$17,000 more for the 3 Series M3 gets you 5 real differences. At $299/month more, the question is whether those specific changes are things you will use regularly.
Trim-Matched Accessories
These add-ons are split by trim intent so the recommendations follow the actual use case, not just the same repeated product block.
BMW 3 Series M340i
Value-trim add-onsThese picks fit the M340i best when the goal is covering the daily-use gaps without paying up to the next trim.
BMW 3 Series M3
Step-up trim add-onsThese picks suit the M3 when you want the accessories to match the nicer cabin, broader utility, or more premium use case.
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Specifications shown combine licensed third-party automotive data with official manufacturer, EPA, and NHTSA source material for the 2026 model year. Actual pricing, features, and availability may vary by region and dealer. Always confirm details with an authorized dealer before making a purchase decision. TrimAtlas is not affiliated with BMW or any dealership.
Page updated 2026-03-18. Verify equipment, pricing, and regional availability with the manufacturer or dealer.