If you're looking for a compact executive, we'll tell you the 320d is the best of the bunch. There should be some great news for sun-lovers, then, because BMW has finally decided to slot the same engine into its 3 Series Convertible.
So, if you're wearing your sensible hat, the 320d is the drop-top to go for, right? Surprisingly, it's not.
Why? Well the 320i (the 2.0-litre petrol) is more than £2000 cheaper to buy, and will be worth a tad more when you decide to sell.
Diesel is around 12% pricier at the pumps, too, so although the 320d doesn't drink as much juice, you'll have to do 35,000 miles a year before you start to see any savings.
Then there's the weight. The Convertible weighs a quarter of a tonne more than the coupe or saloon, largely because of the folding metal roof and added structural support.
That's the equivalent of chauffeuring around a grizzly bear everywhere you go, so it could do with more oomph than the coupe.
The added bulk doesn't go unnoticed through the corners, either, but for a convertible, the 3 Series handles superbly - just not quite as sharply as the coupe it's based on.
The suspension's a bit firm and tall passengers won't want to ride in the back, but the driving position is spot-on and the cabin is beautifully made.
Overall, the 320d is a fine convertible, but bettered by others in the same range. With ever-increasing fuel prices, the 320i is the choice for penny-pinchers, and the more powerful 325i has the best all-round talents.
• The BMW 320d Convertible is on sale now from £33,440.