01 · Overview
The M-Roadster that BMW never built
When the Z4 appeared, there was no M model — the Z4 M did not arrive until 2006. Alpina filled the gap: at the IAA 2003, Buchloe presented the Roadster S, built on the Z4 3.0i.
The hand-built 3.4-litre six-cylinder E5/2 comes from the B3 S and is a bored-out version of the S52B32 — the engine used in the North American M3 E36. 300 PS at 6,300/min, 362 Nm, along with a six-speed ZF gearbox and a final drive ratio altered from that of the Z4 3.0. Unlike BMW, Alpina deliberately offered no automatic.
It was offered in two trim levels, Standard and Luxury. As is typical for Alpina, the focus was not on top-end revs but on elasticity and everyday usability.
02 · History
Einordnung
Three dates for context.
- 2003 Unveiling at the IAA in Frankfurt. There had never been an Alpina based on the Z3 — so the Roadster S does not replace a predecessor model.
- 2006 BMW introduces the Z4 M with 343 PS. The Roadster S is discontinued.
- 2006 Final year of sale. How long production actually lasted is reported differently by the sources.
03 · Engines
The E5/2
No N52 and no M54 — a distinct approach from Buchloe.
ALPINA E5/2 · inline six-cylinder verified
Hand-built in Buchloe, 3.4 litres displacement, shared with the B3 S based on the E46. Its foundation is not the modern N52 of the donor car, but an enlarged version of the S52B32 from the North American M3 E36. The final drive ratio was changed from 3.07 to 3.23 compared with the Z4 3.0.
Technische Daten anzeigen
| Hubraum | approximately 3.4 litres |
| Leistung | 300 PS (221 kW) at 6,300/min |
| Drehmoment | 362 Nm |
| Getriebe | 6-speed ZF, manual |
| Achsübersetzung | 3.23 instead of 3.07 |
Wikipedia · Alpina Archive · auto motor und sport
04 · Engineering
Alpina instead of M
Two trim levels
Deliberately without automatic
Two top speeds
Technical data — final drive ratios & gearboxes
- Power
- 300 PS (221 kW) at 6,300/min
- Torque
- 362 Nm
- 0–100 km/h
- 5.3 s
- Top speed
- 265 km/h with soft top, 270 km/h with hardtop
- Gearbox
- 6-speed ZF, manual
- Final drive ratio
- 3.23
Contradictory and therefore not listed as a fixed production period: Wikipedia states 2003 to 2007 in the running text and 2004 to 2006 in the data table, classic.com states introduction in 2004, production until 2005 and sales until 2006, auto motor und sport states 2004 to 2006, AutoScout24 and encyCARpedia state 2003 to 2005. Only the unveiling at the IAA in September 2003 is confirmed.
The production figure of 167 units comes from classic.com and is so far only singly sourced.
05 · Buying guide
What matters
With 167 units built, documentation is decisive. An Alpina without complete paperwork is difficult to assess.
Alpina vehicle number and papers: Alpina is an independent manufacturer, not a tuner. The attribution must be correct.
Engine condition: The E5/2 is hand-built and shares its base with the B3 S — parts are correspondingly special.
Completeness of Alpina parts: wheels, trim, interior. Retrofitted BMW parts significantly reduce the value.
Clarify insurance in advance: Many insurers classify Alpina as a distinct make, often considerably more expensive than the base BMW.
06 · The competition
The competition
BMW Z4 M (E85)
From 2006, the factory counterpart — 343 PS, but designed with a more rev-oriented character.
Porsche Boxster S (987)
The class benchmark, against which the Roadster S had to hold its own.
07 · Sources
Sources & Further Reading
Primary sources are Wikipedia and the Alpina Archive, cross-checked against classic.com and the trade press. Production period and unit numbers are source-dependent; the evidentiary situation is stated in the technical data.