Last month I popped the tractor into a local independent garage to have a small PAS leak sorted. While it was there, I had a similar age 318i touring, and ignoring the obvious it made for a very interesting comparison. I’ll compare them in terms of looks, performance, ride, economy and interior, and finally discuss the main point: overall value. So the 318i; here it is next to the M5 on the driveway.

Looks

To the untrained eye (for instance, my father’s) it’s the same car. I appreciate the high gloss shadow line and the white indicators – with chrome around the windows and orange corners it’d look really basic. That said, those 16″ wheels are tiny (the tractor wears 18s – even its winter wheels are 17s – those 16s wouldn’t even fit over my front brakes!) and the SE bumpers look far more placid. The chrome kidney grilles complete the “wouldn’t say boo to a goose” image. For comparison:

Beauty is of course in the eye of the beholder, but I felt the 330d won this round.

Performance

This comparison isn’t supposed to be a one way street, but I must get the numbers out of the way. Compared with my dyno figures the 318i has 70% of the power and just 48% of the torque. On the road that difference is painfully obvious under all circumstances, so again, the 330d wins this round hands down.

Initially I tried to motivate the 318i into proving that it was in any way an Ultimate Driving Machine, but I soon realised it was best to waft. This worked well: the 318i is extremely smooth and makes a delicious noise. Especially in warmer weather with the windows down I find myself operating the 330d’s accelerator fairly digitally; the rush of the torque wave and the sound of the wastegate releasing are extremely addictive, so it was good to be more mature with the controls and thus travel with a little more comfort.

Ride

On the subject of comfort, having ridiculed those teeny wheels I soon noticed the transformation in ride quality. It’s fair to say that while a lower ride height on stiffer springs and ultra-low profile tyres makes for some eye-popping cornering, it also makes for a spine shattering ride over bumps and pot holes. On comfort suspension and big floppy tyres the 318i was a real pleasure over Woking’s battered roads. The compromise of course arrived with each corner, but the whole package makes sense: without performance and supportive seats there’s no point trying to corner fast, so I didn’t. Even so, without question the 318i wins a round here.

Economy

I’ll lay down the facts here, and we’ll come to the topic of overall value soon enough. When I was really, really kind to the 318i, I got 30mpg. If I tried in vain to extract some performance, that figure tumbled. The 330d either does 40mpg on a sensible run, or 35mpg if you drive it like an animal. Yes, diesels are renowned for economy, but smaller petrol engines shouldn’t be this bad. I guess here the sheer weight of the car meant that the engine was always strained. In any case, a definite win for the 330d.

Interior

Compared with a late E46 M3 the 330d certainly lacks some switchgear on the panel in front of the gearstick. However, inside the 318i was a bit of a barren wasteland.

The lack of sat-nav was the most obvious visual difference, but the flat seats and narrow steering wheel certainly left the 318i feeling substantially less focussed. Here’s a comparison with the 330d taken when I fitted the new E46 M3 steering wheel (but before the black leather illuminated gear shifter).

So while there was nothing wrong with the 318i’s interior, getting back into the 330d felt a lot more right. 330d win, again.

Overall value

Now we come to the point. Given that the 330d gives better performance, is a more pleasant place to be and costs less to fuel, what are the benefits of the 318i? The smaller petrol engine still has two clear advantages: it’s cheaper to purchase, and it’s cheaper to maintain. Brakes cost less, services are cheaper, tyres I imagine are a fraction of the price. Yet the 330d no doubt holds its value better.

Clearly I’d rather have the 330d – that’s why I’ve got one. But if pushed for funds would I rather have a 318i touring than a similarly priced Vectra estate? Yes – it’s properly built and the correct wheels are driven. It’s a good car, but the 330d is simply excellent.