BMW 420i vs BMW 520d

What's the difference?

BMW's new 4 Series blasted onto the world stage with a chonky schnozz on it that only a mother could love. If BMW didn't want anyone to look at the rest of the car, it did a cracking job of it, because everyone had something to say about the big gnashers now grafted to the 4's front end.

I was nervous about it, too, because the 4 Series has always been so elegant and the current 3 Series - on which it is based - is quite nice to look at. It also threatened to overshadow just how good a car the BMW 4 should be, based as it is on the excellent 3 Series.

And, of course, one also had to wonder if a sports coupe like this would be any good around town. Limited vision? Hard to get in and out of? A true four-seater, or just a squishy 2+2? So many questions. 

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?