You'll be pushed to spot it, but BMW's X5 has changed, and for the better. Aside from mild nips and tucks around eyes, nose, chin and bum, BM's larger 'Sport Activity Vehicle' looks as it always did, but underneath it's very different. Piggy-backing the new X3, it adopts a more sophisticated all-wheel- drive system, xDrive, and gets revised engines with more power and torque, plus new six-speed transmissions, depending on model. All of which makes it quicker, more refined, in most cases cleaner and more economical - but most of all a noticeably better drive both on and off road.

Power first: the 231bhp 3.0i petrol six carries over, but with a six-speed manual it nicks a couple of tenths from 0-62mph (at 8.3 seconds) and a little top end, at 134mph for the Sport. The 4.4i V8, now with Valvetronic, jumps from 286 to 320bhp, dropping the 62mph time from 7.5 to 7.0 seconds, with a 149mph max for the Sport. And the 3.0d turbodiesel gains most of all, up from 184 to 218bhp, and from 302 to 369lb ft - a 22 per cent gain, and the same lb ft as the V8 M5.

But the truly impressive bit is that, whatever the engine, the X5 is now more capable of using its performance with real composure. xDrive, with its electronically activated multiplate centre clutch, reacts faster and more subtly than the old mechanical layout. Press-on handling (and steering feel) benefit significantly - to the extent that you can probably drive the X5 quicker and more assertively on the road than any other big 4x4. It's also more capable off-road. It even feels smaller than it is, and it's comfortable.

There's more to come in May, with an uprated 4.8is. The original, 347bhp 4.6 promised 150mph and 62mph in 6.5 seconds. The new one will be quicker. BMW says, 'all will be revealed in due course, but expect it to raise the roof'.