BMW 4 Series vs BMW 520d

What's the difference?

Without a whole lot of fanfare BMW has slipped yet another model into its Australian line-up.

Sitting alongside existing coupe and convertible variants, the new 4 Series Gran Coupe follows the template established by the previous gen version. 

A sports luxury four-door with a sleek, fastback twist, it provides a more adventurous alternative to its close 3 Series cousin. 

Offered in three grades, this is the M440i xDrive, the 3.0-litre, six-cylinder, all-wheel drive 4 Series Gran Coupe flagship. 

It competes with premium all-wheel drive four-doors like Audi’s S5 Sportback, the Jaguar XF P300 R-Dynamic HSE, and the Mercedes-AMG C 43.  

Eco-friendly vehicles are the leather pants of the new-car world; it takes a lot of money to make them look good (but people who own them think they look fantastic regardless). If you don't have a gazillion dollars to drop on a Tesla,  then it's a one-way ticket to Prius town. And really, who wants that? 

But what if it didn't have to be that way? Behold the BMW 530e iPerformance.

Seemingly tired of waiting for the Australian Government to introduce any sort of meaningful subsidy for green cars, BMW has made the choice simple: you can have a petrol-powered 530i for $108,900, or opt for the plug-in hybrid 530e for... $108,900. This is truly revelatory thinking.

There's no specification penalty, either, and the hybrid will power to 100km/h in an identical 6.2 seconds, so you're not even any slower. But you are sipping less fuel, emitting less C02 and basking in the general smugness, and sweet silence, that comes with feeling like you're saving the world.

So what's the catch?