FORGET the near invisible facelift, all-new diesel transplant, different cabin trim, and downward movement of some key options in the revised Mini.

Yes, all add something fresh and – in the case of the engine – worthwhile to the ownership experience.

But it is the redesigned side indicators that speak volumes both about what the 2011 R5X LCI (for Life Cycle Impulse – thank you for that, Germany) is all about, and why the baby BMW is in a different class compared to rival Mini wannabes.

The blurb about the side blinker unit is understated: “The glass cover now features concentric circles underlining the iconography of the indicators.”

On paper it is easy to miss that, but in the metal, those “concentric circles” are an arresting design detail that – for this particular beholder anyway – captures the essence of the original British Motor Corporation’s AD015 Mini of 1959. It is a delicious morsel of nostalgia that connects new with old, taking us back to that bygone era. The way the orange globe within the lens floats there further evokes such feelings.

Since the new Mini does not have an original design bone in its body, BMW ought to throw out that ugly oversized speedo and concentrate more on honing such beautiful classic detailing. Fiat showed the way with the masterful 500, and it is a far cry from the blundering approximation of the current VW New Beetle and embarrassing Ford Thunderbird of a decade ago.

Obviously, the new indicator is also a manipulative move by BMW to reinforce the existing Mini’s timeless heritage in the face of the Audi A1 and Citroen DS3 onslaught – a pair that forgo icon plundering (except for the French car’s name – shame on you, Citroen) for a welcome dose of modernity.

But none of the competition quite drives like the Mini. While they might have similarly darty steering, the BMW feels more planted and composed, more go-kart like (to borrow the company’s own description) that every single Mini past and present share. The British-built car feels expensively engineered and not related to anything else on the road. The A1 (VW Polo), DS3 (C3/Pug 207) and 500 (Panda, Ford Ka) do. Maybe it is their torsion beam back ends, or maybe it’s the fact that the Mini is truly bespoke.

It’s also become ubiquitous – and will be more so as BMW continues to stretch (to breaking point?) the definition and meaning of Mini.

Anyway, on to the biggest change, the diesel: Out goes the old PSA-derived 1.6-litre diesel (80kW/240Nm, six-speed transaxles), for an all-new BMW-built unit related to the 2.0-litre found in everything (including alphanumerical) numbered between One and Five. This is the first transverse application for a BMW engine we understand, and not the last, as a family of new front-drivers wearing the roundel is on its way, apparently – hence the change for Mini.

The changes the BMW diesel brings to the Mini D justifies the $1000 price hike in our books – much greater low-down torque that is spread across the rev range for better acceleration and response. It seems quieter and smoother to boot as you give it the boot, too.

We reckon the diesel has that instantaneous torque that the otherwise all-over-in-a-flash A-series lump in the old BMC Minis delivered, connecting the generations a little more – except that today’s car keeps on piling on the thrust, in a delightfully addictive sort of way. That the chassis is more than able to cope with the torrent of torque further heightens the fun. We’d certainly have one.

But this is offset by the greater weight of the oil swiller over the front wheels, which takes some of the zig and zag out of the handling. You would only really ascertain this if you a. already drive a petrol-powered R56 (hatch) Mini or b. you jumped straight out of the diesel and into the regular (unblown) Cooper.

The latter underwent a small raft of upgrades last March, with slightly more power (up just 2kW) and minor efficiency gains. Really, after the Mini D experience, this isn’t enough, especially for the prices BMW demands. The car underneath feels far worthier than what the sweet and revvy but ultimately undernourished 90kW 1.6L petrol can provide.

Yet get it on a roll, and the undiluted feel and response from the helm makes it an absolute driver’s dream, and ultimately even more enjoyable than the diesel. Only the ride on the standard 195/55 R16 tyres (runflats are optional at this end of the Mini spectrum) is a little on the firm and vocal side, although not unpleasantly so.

However, overshadowing both for pleasure and upped pulses is the fast, slick, and agile Cooper S. Arguably the pick of the whole Cooper range (including the rorty JCW John Cooper Works), it injects real racy sports car flavour to proceedings, but without the raw, at times hard edge of the appreciably quicker JCW cars.

Other observations: the longer-wheelbase Clubman (R55) models are smoother, slightly less darty and probably the better everyday driving proposition, unless ultimate Mad Mouse antics are the order of the day, in which case stick with the hatch (and forget the somewhat leaden-by-comparison R57 Cabrio). We’d love to see the new diesel in the Clubman, mind.

What else? The newcomers’ darker trim on the dash and steering wheel take away some of the garishness that mar the Mini, although that uselessly oversized speedo is now a dated eyesore. We appreciate the slightly more fathomable switchgear, and we continue to marvel at the Teutonic solidity of a car built in Cowley, England.

Finally, BMW provided a motorkhana test track across a variety of varying (often slippery) surfaces, to highlight just how much of a driver’s car the Mini continues to be. In that context the Post Modern Brick is still a one-of-a-kind proposition, reminding us of just how thoroughly engineered as a driver’s car the current car really is.

So, diesel aside, the changes are pretty, ahem, minor. The cabin is still twee the thick and upright pillars and mirrors still make too much wind noise the ride on the larger-wheeled Minis can still feel a tad un-comfy the options (though cheaper in some cases) are still exxy and the packaging compromises – tight back seat, joke boot, stupid left-hand drive suitable-only Clubman suicide door, divided rear vision – remain.

But this car can still put a smile on your face in the way the competition simply cannot. And the latest iteration seems truer to its past (in details large and tiny) than we can expect any retro car to be. Those concentric circles in the indicators are just another lovely reminder of that.

We look forward to the ongoing Mini evolution.