The BMW comes with the world class 3.0 litre straight six turbocharged engine that does a great job of getting you from A to B already, and the Lexus has a 3.5 litre V6 powerplant that can do exactly the same. And it is right here that I don’t see eye to eye with the manufacturers about how they are saving the planet with these two particular cars.

I get that Hybrid technology must be developed and used as a stepping stone to greater things such as complete electric offerings and the like, but then at least use a small capacity very efficient engine to start with.

Audi is staying out of this local war by not bringing their A6 Hybrid that runs the 2.0 TFSI engine to start with before getting electrified, and it would seem so is Mercedes Benz, but since these two here are intent on taking each other on, we took them to Gerotek to see which one comes out tops in pure tested terms.

The 5 Series immediately felt the far livelier of the two thanks to its force fed engine that now delivers 250kW and 450Nm thanks to the addition of electric assistance. And the battery seemed to quickly recharge on the run and this meant that there was always good urge on hand.

This was proved when I did four back to back 1km runs with the BMW and the Lexus, and the 0-100 km/h sprint for the BMW was done in a mere 6.02 seconds( 0.4 second drop off in the 4th run), the 1km distance covered at 211.47 km/h (5 km/h drop off) while limiting at 250 km/h regardless.

The Lexus on the other hand could only manage a 7.26 second 0-100 km/h first run with a huge drop off of 1.72 seconds by the 4th run, with a 1km speed of 203.55 km/h (down to 195 km/h by the 4th) and also running a limited 250 km/h top speed.

This culprit here is that firstly the naturally aspirated powerplant, that  makes 252kW and a claimed 620Nm on paper,  loses 18% of this due to the lack of oxygen in the thin air up here.

 And then the battery seemed to drain quicker and take longer to get back on speed than when compared to the BMW, so the urge on hand in the Lexus was not always as electric as you would want it.

In defence of both cars though, they will seldom be driven hard like this for extended periods of time, but should they be, the BMW will stay strong while the Lexus wilts and starves from lack of oxygen.

And in saying this, I never felt the urge to drive the Lexus hard when I was out on the road because the car felt best when taking it easy, which again renders it pointless when I could have being doing this with a far cheaper GS 250 and probably still use the 9.0 litres per 100km I got with the Hybrid.

The BMW on the other hand invited you to drive it harder, because should the battery not be adding much, you still had all that turbo power to play with. Again though, hardly the right way to go about saving the planet, even at a very decent 10 litres per 100km (both cars came nowhere near their claimed figures).

I would opt for a better priced 530d or even 520d if I was to think that I was making the bunny huggers happy. The big trick of course, should you have to choose from these two, is that the Lexus comes with a full house of luxury for its starting price of R753 700, whereas the BMW starts at R757 300, but you could easily spend another 100k getting the spec right to rival the Lexus in this area.

The ride and the looks of the Lexus has improved somewhat, but that slow CVT gearbox versus the slick shifting eight-speed auto of the BMW further lets down the dynamic side things, but neither of them makes real sense to me as planet savers, as you would be doing the world a bigger favour by driving a smaller capacity and cheaper turbo- diesel type car to start with.