BMW's latest newcomers are being launched in conjunction with visits to the Guggenheim museum in Bilbao. Like the transcendental exhibits from Yoko Ono on display, they make you do a double take, wondering if it's a hidden message or some act of mockery.

These are the ying and yang of the 4-Series range.

BMW is slicing and dicing its mainstream market with a mix of variants of the 3-Series that would make your head spin. Not content with creating mass confusion with its engine range naming convention, it has moved on to add multiple formats to every range.

To quickly summarise its moves in this particular section of the market: the 3-Series remains BMW’s regular mid-size saloon, touring estate and bulbous GT version. All practical and efficient. The new 4-Series incorporates the coupé derivative and the two new variants launched here, the X4 and the Gran Coupé. The former is really rather odd; the latter is a revelation.

First to the X4. This is a smaller version of the X6, a car that itself has divided opinion since launch. Adding coupé looks on an SUV platform always seemed a pointless exercise, but the beefy no-compromise styling of the X6 made us admire it, if only for BMW’s chutzpah in bringing it into existence.

The X4 is another matter. Out goes some of the radical design in favour of a soupçon of practicality, yet that’s always compromised when compared to the X3. And it lacks the deftness of a normal 4-Series coupé – in whatever format. The front styling is as aggressive as the rest of the popular X range from BMW, yet that dominance seems to melt into a level of uncertainty as you move towards the rear – not quite the coupé look of the X6, nor the functionality of the X3. It’s as if the X4 isn’t confident enough to live up to its own billing.

Extra weight
There's no getting away from its extra weight either, and, even with the powerful 3-litre 313bhp petrol engine in our test vehicle, there were times when it needed to catch its breath before charging into the twisting bends. We can only imagine that the engine favoured by Irish buyers – 190bhp 2-litre diesel – would not set the world alight in the X4.

While there is plenty of legroom in the back – at least compared to a regular coupé– the rear seat headroom is noticeably more restricted than in the equivalent X3, while visibility through the postbox rear window is heavily compromised. A rearview camera would seem a must.

The new X4 arrives in showrooms on July 12th with prices starting at €57,720 for the entry-level 2-litre diesel auto SE version. That’s a sizeable jump from the equivalent X3 2.0D SE auto priced at €51,105.

And so we come to the 4 Series Gran Coupé, a car that on paper seems little more than a niche within a niche. Yet this car makes you reconsider not only the very existence of the regular coupé but also the need for the 3-Series saloon. It’s simply fantastic.

First off is the looks: all the eye-catching appeal of the coupé styling, but with four doors. This format won fans when it first emerged in the Mercedes CLS, and has since starred in the popular Volkswagen CC. BMW’s 6 Series Gran Coupé has done well in its niche but this is the first time that the brand has built a four-door coupé for the more mainstream premium market.

Legroom
What you get is a proper, practical premium car, with impressive legroom in the rear – enough to cater for two adult passengers – and a decent boot of 480 litres with the rear seats up, stretching to a workable Ikea load-lugging 1,300 litres with the seats down.

The engine range is the same as in the regular coupé, as are the trim levels and styling. What’s more – and this is the biggest boon – so is the price. You can get the extra practicality, the family-friendly space and the coupé looks for exactly the same price as the current coupé. Not one euro more between the 420d SE coupé and the 420d SE Gran Coupé. We’re still not sure how BMW came up with this pricing model, but we’re delighted and it makes you wonder why anyone would opt for the regular two-door version.

Issues
On the road the Gran Coupé loses none of its sportiness, though it also suffers the same issues as the regular coupé in that it's not as nimble as the 2-Series coupé, and therefore not as much fun to drive. You can opt for comfort mode or a variety of sports modes, which adjust the ride, steering and throttle response. Strangely, this car is most at ease in sport mode, feeling a little woolly and imprecise in comfort. The ride is also best in sport mode, and while you would expect it to crash hard on speed bumps, it's remarkably well poised.

Ultimately, if you are looking for a fun coupé that offers some real sports car appeal – and that will put a smile on your face every time you drive it – then the 2-Series is by far the best buy in the BMW range. It will also save you money – up to €12,000 – on its larger siblings.

If you need a little more practicality but still want the sharp coupé looks and performance, then the Gran Coupé is the one to buy. Even those considering a 3-Series saloon who rarely use the rear seats should give serious consideration to this one.

With the Gran Coupé and the 2-Series on offer, it’s hard to see why anyone would opt for the regular 4-Series coupé. While the X4 left us bemused, the 4-Series Gran Coupé left us besotted. Perhaps the musings of Yoko Ono have rubbed off on the Munich executives.