Sizzling siblings: BMW's 420i and 435i

BMW's entry-level 420i fares well against the more accomplished 435i

In the music video for their new duet Can't Remember To Forget You, pop divas Shakira and Rihanna send temperatures soaring. In a sizzling scene, the duo frolic in bed clad in near-identical black lingerie, only to emerge later in a naked embrace.

The 420i is the entry-level variant of BMW's new line of 4-series mid-sized coupes. Comparing it with the 435i - its top-of-the-range sibling reviewed in Life! last October - is a little like asking who is hotter: Colombian bombshell Shakira or Barbadian star Rihanna.

Both set pulses racing, but each has her own fans.

The 420i has an appreciably lower price tag of $239,800, or $76,000 less than the 435i. For potential buyers, it comes down to what the $76,000 cut means.

But car shopping is not solely about comparing equipment lists, so a meaningful place to start is to look for similarities between both cars.

Visually, only a car buff can tell the 420i and 435i apart without looking at the badges.

The 420i runs on 18-inch multi-spoke wheels and has a single-exhaust tailpipe, while the 435i has larger 19-inch five-spoke rims and twin tailpipes.

But comparing the rims is like asking whether 2-inch or 3-inch Jimmy Choos are sexier.

Both come with sunroofs and have the same svelte lines with a hint of the Z4.

The similarities extend into the interiors. The 420i has the same sporty steering wheel, inviting layout and snug seats as the 435i.

But peek into the corners behind the A-pillars and you will find Harman Kardon speakers missing. The 420i makes do with a factory-fitted audio system, which should make little difference to the average ear.

The biggest difference lies under the bonnet.

The 420i packs a 2-litre turbo putting out 184bhp and 270Nm of torque, which has considerably less poke than the 435i's 3-litre turbo, which cranks out 306bhp and 400Nm.

The difference means the 420i sprints from zero to 100kmh in 7.3 seconds, over two seconds slower than the 435i's 5.1-second sprint.

At kickdown, even in Sports mode, there is a whiff of hesitation before the 420i launches into a subdued gallop.

The smaller engine, however, means fewer visits to the petrol station. On paper, it has a lower fuel consumption of 6 litres per 100km, compared with the 435i's 7.4 litres.

On the move, the car's eight-speed transmission is a gem. Gear changes are silky smooth and imperceptible, making the pedal shifters redundant because the transmission is capable of finding its own sweet spot.

The 420i does not have bells and whistles such as a rear-view camera, adaptive headlights and heads-up display. But its GPS driving instructions are displayed on the instrument cluster, which is as useful.

Although the 420i retains BMW's familiar point-and-go steering feel and near-perfect body control, my biggest grouse is that it lacks variable-speed steering, which is common in cars well above $200,000. Drivers can forget about parking the car using just two fingers to turn the steering wheel.

And for a car in its price bracket, some adjustments are still manual, such as the sunroof shade and steering-wheel adjustments for rake and reach.

BMW agent Performance Motors expects the 420i to have a wider appeal than the 435i.

I will even venture to say that the car will not just appeal to those who baulk at the hefty price of the 435i, but it may also draw sales away from the 3-series.

Price-wise, the 420i sits midway between the entry-level 316i and top-of-the-range 335i sedan. But compared with the more common 3-ers, it has an alluring X-factor - like Shakira and Rihanna.

Its decent boot space, four-seat layout and adequate rear legroom for averagesized adults make it practical enough for singles, dating couples or those married with one child, if having just two doors is not an issue.

At the end of the day, BMW drivers will buy according to the depth of their pockets, be it the 420i or 435i.

The 435i will wear the unchallenged crown as a top-of-the-line car. But the 420i will likely be the one which gives the new range the much-needed model visibility, given its lower price tag.

So there is no point asking which or who is hotter - 420i or 435i, or Shakira or Rihanna.

Both cars and divas are equally so.