Road Test: BMW X4 xDrive20d SE 5dr

BMW is disgorging so many new models, it's running out of numbers. After i3 and i8 and X4, I dunno what it'll call the upcoming front-drive hatches. So how come BMW is wantonly spending precious new numbers on cars that already had perfectly good badges? The 3-Series Coupe has become, by deed poll, the 4-Series. The rationale is this: odd numbers are for sensible bodies, and even numbers are for cars of a coupe-ular disposition: 6-Series, 8-Series, i8, X6 and X4. So it's 4-Series for this. Next year's 2dr derivatives of the current 1-Series will go by the 2-Series handle. Got all that?

The 4 justifies the new name by moving visually away from the 3. It was always lower and squatter, but now it's also slightly wider than a 3-Series (and a lot wider than the old one), not just in the body panels but the track. Visual tricks add to the effect: the glasshouse narrows toward the rear - it's just a four-seater - so the rear wings look broader. The channel along the side of the body at doorhandle height becomes shallower as it fades into the wing, as if the wheels are bursting out through the body.

Inside is a regular 3-Series dash, but you sit slightly lower relative to it. The suspension is 10mm lower, too. Mind you, that's all within the range of the seat-height adjuster. Rear room is fine for legs and feet, though marginal for a six-footer.

So BMW sportified the proportions. What about the drive? Mass is down versus the old coupe - minus 25kg for the same engine and 45kg for a 428i, as its 4cyl replaces the old 330i six. Versus the current 3-Series, the steering has been remapped, and the hub carriers are different to take advantage of the track change and the lower suspension and c-of-g.

I'm driving a non-UK spec: a 435i Sport. In Britain, the nearest spec is Luxury. But you can option up this car's adaptive suspension, 19s and variable sport steering 'box. Yet, when you ask the 4-Series project leader, he admits he'd have a 428i, saying it turns more nimbly. The 435i (306bhp and 295lb ft) has the legs over the 328i GT that I drive daily (245bhp and 258lb ft), but by a smaller margin than I expected. The 4cyl 328i is gruffer in the mid range, mind, but, heck, as the six-pot 435i goes to its 7,000rpm red line, it doesn't quite sound as delicious as you'd want when the name above the door is Bayerische Motoren Werke. Still, I'm being petty over small degrees of excellence. It's quiet and lag-free, and operates over a huge rev range, while shunning fuel stops. The 435i might feel rapid, but it's even more rapid than it feels.

The steering disappears in your hands. It just works, and you stop noticing it after the first corner. It's not so eager as to be twitchy, nor so slow that you're ever twirling your arms. Never bashed about by bumps or tugged by engine torque. Most of all, it's instinctive and progressive, so you can place the car perfectly on the road and (unless you've made it slide) never have to correct your input. The 4 has mild understeer in the steady state, to safely impart knowledge about how much grip you've got. Add throttle, and the rear tyres will edge out, depending on which of the electronic waiver forms you've signed with the three-stage DSC. Anyway, oversteer is remarkably correctable and progressive and tidy. Only in tight hairpins is an LSD missed.

Comfort mode gives surprising and relaxing ride suppleness, but it can get floaty when you press on. The Sport mode cancels that, slightly sharpens turn-in and tautens things usefully mid-bend. But even going slowly on straight roads, when stiffness isn't wanted, Sport gives an annoyingly knobbly ride. It's not adaptive enough, so I'm incessantly jabbing at the switch. The chassis engineer says it's a hardware issue, because the dampers operate between differently set limits in each mode. But, when pushed, he adds it's also a marketing one. People want to press a switch and feel where their money went. More fool they.

That niggle aside, this is a machine whose nearly every atom operates with high competence. I've filled my allotted space and didn't have room for the infotainment and connectivity and quality and driver assistance, but all those are right up there too.

Competence is one thing; character, another. Starting with the 3's near-impregnable excellence, all the 4's detailed differences make only a detailed difference. The 4 was never going to muck things up. But neither has it risked getting edgier.