MCARMARKET

BMW Z4 M Roadster

The E46 M3's S54 in a compact roadster with hydraulic steering — the last naturally aspirated M roadster and a quietly brilliant driver's car.

BMW Z4 M Roadster — 2006–2008

The Z4 M Roadster took the E46 M3's S54 engine, six-speed manual and CSL-derived steering rack and installed them in the flame-surfaced Z4 body. It is the only Z4 with hydraulic steering, and the difference in feel is immediate.

It is more rigid, more sophisticated and less alarming than the Z3 M it replaced, with stability control and a properly located rear suspension. It also sold in small numbers, which has kept it rare.

For anyone who wants an E46 M3 experience in a smaller, open car, this is the answer, and prices have not yet caught up to the coupe versions.

Year by year

  • 2006

    Launch year with the S54 at 330 hp, six-speed manual only, and the CSL-derived hydraulic steering rack.

  • 2007

    Minor equipment updates. Individual paint and interior combinations become more common.

  • 2008 — final year

    Last of the E85 M Roadsters before the E89 Z4 replaced the line with no M version.

The good and the bad

Positives

  • +S54 engine with the full 8,000 rpm experience
  • +Hydraulic steering with genuine feedback
  • +Manual-only, rear-wheel drive, no automatic option
  • +Rarer than most people realise
  • +Considerably cheaper than an equivalent E46 M3

Negatives

  • −Rod bearings are the same scheduled S54 expense
  • −Interior quality is good rather than special
  • −Ride is firm and cabin noise is high at speed
  • −Limited luggage capacity
  • −Divisive flame-surfaced styling

Known faults and what they cost

  • Rod bearings$2,500–$4,000

    Standard S54 preventive service; ask for documentation.

  • VANOS solenoid and hub bolts$700–$1,800

    Same items as the E46 M3; update the exhaust hub bolts.

  • Cooling system$1,000–$1,600

    Radiator, water pump, thermostat and expansion tank on an age schedule.

  • Soft top and rear window$1,000–$2,200

    Wear, shrinkage and hydraulic faults on the powered top.

Pre-purchase inspection checklist

  • 01Rod bearing documentation with mileage and part numbers
  • 02Cold-start VANOS rattle check and warm idle quality
  • 03Full soft top cycle test including seals and rear window
  • 04Cooling system age and service records
  • 05Check for even tire wear and correct alignment
  • 06Verify the CSL-derived steering rack feel — heavy and direct is correct

Modifications for longevity

  • Rod bearings

    Preventive replacement at 60–80k miles with updated shells.

  • VANOS service

    Solenoid, seals and updated hub bolts as one job.

  • Cooling system

    Full overhaul every 8–10 years.

  • Soft top care

    Regular cleaning and protection; exercise the mechanism monthly.

  • Oil discipline

    5k intervals and full warm-up before high rpm.

Modifications for performance

  1. 01Tires and alignment

    The chassis responds well to modern rubber and a proper setup.

  2. 02Exhaust and tune

    Around 350 hp with a much better induction and exhaust note.

  3. 03Headers and airbox

    CSL-style intake work adds noise and top-end response.

  4. 04Supercharger

    Possible but do the rod bearings and cooling first.

What they are worth

Still undervalued relative to the E46 M3 and the Z4 M Coupe. Low-mileage manual cars with rod bearing documentation are the ones to buy.

Interlagos Blue and Imola Red carry colour premiums. Expect values to follow the coupe upward over time.

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