BMW Z4 Buyer's Guide
The Z4 is the Z3's sharper successor and our data shows the same two-tier market in embryo: an ordinary 2008 car sold for £1,526, while a 2005 Alpina Roadster S made £25,875. Between those two results sits the entire everyday Z4 world, and most of it can still be bought for four figures.
Know your generations
The E85 roadster and E86 coupé (2003–2009) are the enthusiast's generation: hydraulic steering on early cars, proper straight sixes, and a stiff, flame-surfaced body. The range ran from the 2.0i and 2.2i fours and small sixes through the 2.5i, 2.5si and 231bhp 3.0i to the 265bhp 3.0si; above them the 343bhp Z4 M Roadster and M Coupé used the E46 M3's S54 engine and have already been claimed by collectors. The Alpina Roadster S, a 3.4-litre development sold in small numbers, explains our £25,875 result. The E89 (2009–2016) switched to a folding metal hardtop and turbocharging in the sDrive18i to sDrive35is range (up to 340bhp); heavier, more of a boulevard car, cheapest of all today. The G29 (2018 on) shares its platform with the Toyota Supra; the 382bhp M40i is the pick and is still a used car rather than an auction classic.
What to pay
Two sold results: £1,526 for a 2008 Z4 (March 2026) and £25,875 for the 2005 Alpina Roadster S (August 2026), median £13,700, though with this spread the median describes nothing real. The active listings are more instructive about the ordinary market: a 2005 Z4 Roadster estimated at £2,000–2,500 and a 2003 3.0 at £2,000–3,000. That is the going rate for a usable six-cylinder E85. M cars and Alpinas trade far above; our £25,875 result is the only hard number we hold at that end.
What goes wrong
E85 electric power steering columns fail or feel dreadful, and are the model's signature fault; budget for a replacement or recon column on any sloppy example. Roof motors on electric-hood cars burn out (the drain-blocked-wet-boot sequence is usually the cause), rear screens and hood fabric wear, and the usual good-era BMW items apply: cooling system plastics, rear shock mounts, and rust around arches on the worst-kept cars. The sixes themselves are long-lived; the 3.0si's N52 wants its oil level watched but little else. E89 sDrive35i cars inherit the N54's fuel-pump and injector history. On any M or Alpina, provenance and originality dominate value; on a £2,000 car, a working roof and a straight column are the whole inspection.
Our view
A 3.0i or 3.0si E85 at the £2,000–3,000 our live estimates describe is the obvious buy: genuine straight-six roadster performance, hardware shared with millions of 3 Series, and a following that will keep it a viable classic. The steering column is the one flaw worth pricing in; everything else is maintenance. The M cars and the Alpina have already made their move, as our £25,875 result attests. The ordinary sixes are where the Z3 was a decade ago, and they will follow the same path.
