I'm not sure if the middle of winter is a good or bad time to buy a roadster, but I'd fancied a Z4 for a while, and prices had dropped a fair bit since I last looked (tail-end of the summer). I therefore trudged up from Bristol to Manchester to view a couple of good value 2003 3.0 Z4's, just before the New Year. One was grey (good) but needed too much tidying, and the other very tidy but in black (bad) and didn't have heated seats - otherwise I'd have probably bought it. I'm not sure I like cleaning cars enough to have a black one.

I then however spotted a well priced 2004 car a couple of weeks later, and got up to North London before the other punters early one Saturday. It was silver, had a low mileage, the right spec, was in good shape and drove well (like the others). I figured I wouldn't do a lot better for the money, and took the plunge. Strangely; prices for these were all over the place; mileage seemingly not making much difference (though most were low) - but some very similar ones to "mine" were up for thousands more. The car checked out OK on HPI and with BMW Customer Services (who were very helpful), the deposit was down, and so with a heavy heart I put my brilliant E36 M3 Evo up for sale a few days later.

The proportions of the Z4 are typical front-engined sports car but the looks are unusual - from the heavily sculpted, OTT flanks to the neat little inbuilt duck tail spoiler in the rump, as per the M3 CSL. Neat little touches and features abound. I have never owned a convertible before, and felt that was an experience I should try at least once. The interior is refreshingly different with its large slab of brushed aluminium incorporated into the dashboard. My car had the options I considered essential: heated seats (should be standard in the UK!) and a wind deflector. The basic BMW Sat NAV / 6 CD changer and 18" wheels were also nice-to-haves, not that I was too worried by them.

I collected the car a week later. The M25 was nice and quiet and I found the car returning an easy 35mpg or so as I struggled to turn off the unintuitive Sat Nav, which was attempting to send me back to Edgware, for the next hour before giving up and ejecting the DVD. Initial impressions were of an extremely creamy engine and slick gearbox, much more so than my previous BMW M3 (E36), and to a lesser extent the Z3M Coupé before that, although some of that must be due to the Z4’s relative lack of age and miles (17k).

The appalling ride was also immediately apparent – a bucking bronco comes to mind - something that appears fixable by ditching the run flat tyres (as per many owners and the BMW Motorsport division on the Z4M). Rough surfaces currently have the car bobbing and writhing around, and ruts will cause the steering wheel to dart about quite alarmingly. No wonder the contemporary reviews were less than glowing, handling wise!

Torsional rigidity of the Z4 roadster is nearly 3 times that of the Z3, and comparable to a 3 series coupé so, despite the barraging of shocks the tyres transmit through the shell, it all feels very solid. There are no nasty squeaks or rattles or scuttle shake, though the internal mirror does move around a little. The hood whips up and down very quickly, with no catches to mess around with, so it would be rude not to have it lowered as much as possible, especially with the amazingly quick-to-warm-up seats and heater. Hood up it's like driving a coupe: the cockpit feel is reminiscent of my Z3M, if a little roomier.

Although it's all very smooth and grunty, for me the engine peaks too soon, especially in comparison with the ///M's. The M3 gave me the impression of a mighty engine that eventually turned the tables on a car that was carrying a little too much bulk, but once above 5k revs it was very rapid indeed. The Z4 feels so much nimbler and smaller (sports car vs GT car really: and 150kg lighter than the E36 M3), but the M54 lump has done its best work before 6k. I'd like a little more top end so may have to get it tweaked at some point. 250 bhp (up from 231bhp) and 1,250kg has a nice ring to it...and there appear to be quite a few outfits that should be able to sort this out for me...but I'm not sure that the car is ever going to have enough power to scare me in a straight line, unfortunately.

I bought the Z just before its 3rd birthday, which seems to be a time when I have bought several cars, all of them having shed around 50% of their value at this stage, but with plenty of life still left in them. I debated to myself regarding renewal of the BMW warranty (£608 p.a. and £100 excess) but in the end I didn't. I thought it might be prudent to do so for the first year of my ownership, and I've had good service from BMW dealers in the past, but ultimately I trust a good specialist more; and couldn't find any major Achilles heels with the Z4 on the web (famous last words!). The most common issue seems to be with the lacquer chips on the OEM 18" BBS split-rim alloys (which mine has) - they corrode and BMW replaces them as much as the VANOS system on the S50B32 engine in the E36 M3 and Z3M's! Mine need a refurb due to kerbing but I may change them for something else anyhow, maybe even 17's to improve the ride and handling (less possibly equals more in terms of mechanical grip). 255/35/18's do seem a tad extreme for 231bhp.

A trip t’up North for my brothers birthday followed soon after selling the M3, so the Z was pressed into service. The boot was just about big enough for a long weekend, but the golf clubs had to stay behind. My brother lives in a very narrow street and this was my first chance to try and reverse park the Z4 - I found that the best way to do so accurately was to lower the hood as there is a massive blind spot with it up... The car was otherwise perfectly behaved and somehow returned over 39mpg as I pottered along the motorways. I’ll have to check that the computer is accurate, though the daily commute has lowered this figure to circa 33mpg, which is still very good in my book, Germanic efficiency and all that.

With hindsight I should have had the car MOT'd (within warranty) as soon as I bought it: it failed! I was really shocked, as the car is much newer and less worn than my recent modes of transport! Mr MOT man struggled to explain the problem over the phone, so I went to have a look while it was still on the ramps, visions of a cut and shut in my mind. It turned out that there was too much play in one of the front suspension bushes, 2 hours per side to fix he reckoned (but to be fair that was a guess). I called a friendly specialist who said it was a common issue on BMW 3's (with which the Z4 shares many bits) and would take 1.5 hrs to do both. And whilst doing it I might as well uprate them to Powerflex items which would tighten up the feel at the front of the car (and cost less than the softer BMW ones). Sold! The rear tyres were also at the limit, I didn't think they were that bad, but it would explain why the "fun light" flashed on the dash more than expected.

Talking of fun lights, DSC (dynamic stability control or electronic nanny) is a new device to me, but one that I'm sure would have saved me putting my Z3MC into a ditch backwards on a muddy, gravelly corner one winter morn a few years ago. From what I have seen thus far it really is clever stuff, and very progressive. As with ABS it's probably something the EU will insist we must all have - like straight bananas. I'm going to have to experiment with it more.