Z4 vs M2 — Which BMW Should You Buy?

The Z4 (B58) is the better buy for most buyers — it offers a brilliant open‑top driving experience, lower running costs, and a more reliable engine than the M2's S55. The M2 is a sharper, more track‑focused machine, but its higher purchase price, stiffer ride, and known crank‑hub risk make it a specialist choice. For everyday enjoyment, the Z4 wins.

Z4 (B58): 540 enquiries in 2025, £3,800–£6,000 reconditioned supply [EM-VERIFIED / EM-QUOTE]
M2 (S55): estimated 410+ enquiries (S63 proxy), £6,500–£9,500 reconditioned supply [ESTIMATED]
Z4's B58 is one of BMW's most reliable modern engines; M2's S55 has a well‑documented crank hub failure risk
Z4 is cheaper to insure, more fuel‑efficient, and more comfortable for daily use
Over a five‑year ownership window, the Z4 typically saves thousands in running and repair costs

Full comparison, deep dives on each model, five‑year cost of ownership, and which to choose for your lifestyle below.

At a Glance

	Z4 (G29)	M2 (F87 / G87)
Body Style	Roadster (convertible)	Coupe
Engine (typical)	B58 3.0L twin‑turbo I6	S55 3.0L twin‑turbo I6 (Competition)
2025 UK Enquiries (engine proxy)	540 (B58) [EM-VERIFIED]	410 (S63 proxy) [EM-VERIFIED]
Recon Supply Cost	£3,800–£6,000 [EM-QUOTE]	£6,500–£9,500 (est.) [ESTIMATED]
Defining Failure	Coolant leaks (well‑understood)	Crank hub failure
Best For	Open‑top cruising, daily usability	Track days, pure driving focus

The Verdict

For most buyers, the Z4 is the stronger choice. It's more affordable to buy, cheaper to run, and its B58 engine is one of BMW's most reliable modern units. The M2 is a phenomenal driver's car, but its S55 engine carries a known crank‑hub failure risk that can be costly to fix, and its stiffer ride and higher insurance premiums make it less liveable day‑to‑day. If you genuinely track your car or prioritise ultimate chassis response, the M2 is worth the compromise — but for the vast majority, the Z4 delivers 90% of the thrill with far less hassle. The 70% BMW scrap threshold means that on older, lower‑value M2s, a catastrophic failure could push the repair cost close to the vehicle's value, whereas the Z4's lower replacement cost makes it a safer long‑term bet [PATTERN DATA].

Z4 Deep Dive

The BMW Z4 (G29) is the latest generation of the iconic roadster, powered predominantly by the B58 3.0‑litre twin‑turbo straight‑six. The B58 generated 540 enquiries in 2025 [EM-VERIFIED], making it one of the most‑enquired modern BMW engines. The Z4 is renowned for its balanced chassis, precise steering, and the joy of open‑top motoring. The B58's known issues — coolant leaks from the expansion tank, water pump, and PCV valve — are relatively inexpensive to fix and well‑understood by specialists [PATTERN DATA]. Reconditioned supply costs range from £3,800 to £6,000 [EM-QUOTE], with labour at 10–14 hours. The Z4 is also more fuel‑efficient and cheaper to insure than the M2. Full specs and reliability ratings are on the B58 Knowledge Centre, and the B58 failure rate data confirms its solid reputation.

M2 Deep Dive

The BMW M2 (F87 and G87) is a compact performance coupe that has earned cult status. The Competition and later models use the S55 engine — a twin‑turbo straight‑six shared with the F80 M3. While the S55 is not separately listed in our per‑engine data, the closely related S63 (used in M5/M6) generated 410 enquiries [EM-VERIFIED], giving a sense of the M engine demand. The S55 is known for its crank hub failure risk, typically occurring on modified or high‑mileage cars, with repair costs that can exceed £6,500 for a full rebuild. Reconditioned supply is estimated at £6,500–£9,500 [ESTIMATED], with labour at 12–16 hours. The M2 offers sharper handling, a more aggressive stance, and a more engaging driving experience than the Z4, but its running costs and reliability risk are significantly higher. For full details, see the S55 Knowledge Centre and S55 failure rate data (once available).

Five‑Year Ownership Cost

Over five years, the Z4 is significantly cheaper to own than the M2. The Z4's B58 delivers better fuel economy (around 35–40 mpg combined vs the M2's 28–33 mpg). Insurance groups are lower for the Z4, and servicing costs are reduced due to less complex cooling and turbo systems. The biggest difference is the probability‑weighted cost of major failure: the B58's coolant leaks are minor compared to the S55's crank‑hub risk, which can lead to a full engine replacement costing upwards of £8,000. Even factoring in a preventative crank‑hub fix on the M2 (around £1,500–£2,500), the M2's total cost of ownership is substantially higher. The Z4 is the clear winner for anyone who doesn't track their car regularly.

Which Should You Buy?

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Weekend Cruiser / Daily Driver

Z4 — the open‑top experience, refined ride, and lower running costs make it the perfect companion for sunny weekends and everyday commutes.

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Track Enthusiast / Driving Purist

M2 — if you value razor‑sharp handling, adjustability, and a hard‑edged chassis, the M2 is the better tool. Just budget for the crank‑hub preventative work.

💰

Best Value for Money

Z4 — lower purchase price, cheaper parts, and lower running costs make it the value champion. The Z4 delivers exceptional driving pleasure without the financial risk.

🔁

Long‑Term Ownership (100k+ miles)

Z4 — the B58 is proven to be one of BMW's most durable engines, while the S55's crank‑hub risk makes the M2 a more expensive long‑term proposition.

One point worth being explicit about: the Z4 is not a soft car — it's a proper sports car with a fantastic chassis. The M2 is more hard‑core, but the Z4 is more than enough for most drivers. The repair vs replace framework and the 70% BMW threshold apply equally; always evaluate the vehicle's value before committing to a major repair.

Other Performance Comparisons

If you're still deciding between BMW performance models, these comparisons cover the other popular pairings.

M3 vs M4 →

Saloon vs coupe — the classic M showdown.

B58 vs N55 →

Which modern BMW straight‑six is better?

S55 vs S58 →

The two M‑division straight‑sixes compared.

Z4 vs Porsche 718 →

Roadster rivals — which German drop‑top wins?

Whichever model you choose, the same repair vs replace framework applies to the replacement decision once you've bought. Our Engine Failure Index and average replacement cost data provide further context.

Frequently Asked Questions

Is the Z4 better than the M2?

For most buyers, yes — the Z4 offers a more refined, comfortable, and affordable driving experience. The M2 is only better if you prioritise track performance and aggressive styling over daily usability.

Which is more reliable, Z4 or M2?

The Z4's B58 engine is significantly more reliable than the M2's S55, which has a known crank‑hub failure risk. The B58 has minor coolant leak issues, but these are inexpensive and well‑understood.

Is the M2 faster than the Z4?

Yes — the M2 (Competition) has more power (410 bhp vs 340 bhp in the Z4 M40i) and a sharper chassis, making it quicker on track. However, the Z4 is still very quick and more than adequate for road use.

Which is cheaper to insure, Z4 or M2?

The Z4 is cheaper to insure, falling into lower insurance groups due to its lower power and less aggressive image.

Which has better resale value?

The M2 tends to hold its value slightly better due to its limited production and cult following, but the Z4 also depreciates reasonably well. The M2's higher running costs can offset its better retention.

Is the Z4 a real sports car?

Absolutely — the Z4 has a front‑engined rear‑wheel‑drive layout, a responsive chassis, and the B58 engine provides thrilling performance. It's a proper sports car, just with a more civilised personality than the M2.

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950+ Combined Enquiries Analysed from real 2025 UK data (B58 & S63).

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A Real Verdict We name a winner, and explain honestly when the "loser" is still the right choice.

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20+ Vetted BMW Specialists Experienced with both performance models.

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100% Independent No sponsors, no manufacturer influence.

Z4 vs M2 — Which Should You Buy?