In the beginning, listening to an iPod was a solitary pursuit. No one knew what you had on there, so you could load it up with all your favourite tunes, no matter how embarrassing and sugary they might be.

But now you can plug your personal music library into all manner of systems and lay out the contents for the edification of your friends and family.

This is a terrifying development. We all have guilty secrets, things that we’d rather leave buried in the deep, dark, cobwebby corners of our heads. I, for instance, have always rather fancied Esther Rantzen and, worse, in restaurants I’m often tempted to ask for black forest gateau.

I’ll admit to these things. In fact I just have. But I would never have admitted, even to my closest friend, that I recently paid 79p to a man in America to download a rendition of Journey singing a tune called Don’t Stop Believin’.

I know it’s a terrible song. I know there’s a horrible segue in the middle. And I know too that the lead singer has a voice that makes you want to split his head in two with an axe. But secretly I like it, so one day, when the family was out and the house was quiet and empty, I downloaded it to my iPod and since then have spent many happy, albeit slightly guilty, hours on planes and trains listening to it.

But then one day at a party I foolishly plugged my iPod into a pair of loudspeakers. To begin with all was well. There was a bit of the Clash, some Clapton and a smattering of Joe Jackson. People tapped their feet approvingly.

But then on came Journey and one by one everyone stopped talking. Slowly their heads turned to me. “Did you download this?” “Yes.” “On purpose?” “Yes.”

You could have cooked pudding on my face. And I knew that pretty soon we’d reach Kansas singing Carry On, My Wayward Son, which is even worse.

Since that terrible night, my wife has been giving me funny looks. It’s almost as though she’s suddenly found out that I’m that silly Lib Dem bloke who went to a male prostitute. She thought she knew me. But since she found I have Kansas and Journey on my iPod she realises that actually she doesn’t know me at all.

Nor I her. Because recently we were listening to hers, and in among the Dylan and the Yardbirds and the Cream I was assaulted — and that is the right word — by something called Basement Jaxx.

I can only assume that Mr Jaxx won a competition at some point to see who could make the worst noise on earth. It’s an extraordinary sound: like chewing on a mouthful of those polystyrene packaging balls while Flo-Jo runs her fingernails down a blackboard the size of Lincolnshire, and Ireland wins the Glaswegian round of the world pile-driving competition.

I thought Mary J Bilge was bad but Basement Jaxx takes the art of annoying your parents to new and uncharted heights.

As a result I cannot have my wife’s iPod on in the house any more than she can have mine. She thinks I’m Mark Oaten. I think she’s mad.

And funnily enough this brings me on to the new Audi All Road. In essence it’s a slightly raised, slightly more rough-and-tumble version of the standard A6. It’s therefore a quiet 4x4, a subtle SUV and, it must be said, a handsome and inexpensive alternative to that gargoyle of a car, the new Q7.

I liked almost all of it a lot but, like my wife’s iPod, there was a landmine in the mix. As you drive along a small patch of condensation forms on the outside of the windscreen, right in your line of sight. This is the All Road’s Basement Jaxx moment, and it’s so annoying I’m simply going to dismiss the whole car as useless and move on to the AMG Mercedes E-class.

In recent years AMG, which is a sort of tuning division within DaimlerChrysler, has been fitting most of the cars in the range with its supercharged 5.5 litre V8.

It was an absolute animal of an engine. And the animal I have in mind is the hippopotamus. Most of the time it was benign and rather lazy but when poked with a stick it would become searingly violent, very powerful and extremely noisy. Even though it was, perhaps, slightly American in character I liked it a lot.

So I was a bit worried when I heard that it was being dropped from all cars except the SL, and replaced with a non-supercharged 6.3.

This is the engine that was fitted to the E-class I’ve been driving and you know what? I think it’s even better.

Some of the machinegun exhaust clatter has gone but so too has the feeling of heavyweight power. Despite its enormous size it feels light and agile and desperate to rev. And my God there’s some power: huge drums of it, creamy and delicious and easy to pour into any given situation.

The result is a car that’s preposterously fast.

It doesn’t matter whether you use the paddle shift or leave it in D, or even if you’re going backwards. It takes off in a manner that leaves you, your passengers and everyone within earshot genuinely staggered.

Staggered because it really doesn’t look like anything special. E-class Mercs are mostly bought by companies and chauffeur services that can’t quite run to an S-class. They’re middle management cars. You don’t notice them. And you won’t notice the 6.3 either, because apart from some slightly fancy wheels and rather more exhaust pipes than is normal it looks just like the E-classes that line up outside every media haunt at two in the morning.

Nor does it feel particularly exciting to drive.

It’s quiet, it’s remarkably comfortable, and it comes of course with the usual array of Mercedes gadgetry.

So how, you might be wondering, does it stack up to the BMW M5? Well, they both cost about the same, they both have four doors, they are both limited to 155mph they could both top 200 if they weren’t, and they both offer roughly the same sort of space.

I’d say that even though the Mercedes has more power, the M5 is a more thrilling ride. It really does feel very special when you’re in Exit mode, being suicidal. But I hear horror stories about the BMW’s electrics, and to live with every day the more refined, more grown-up Mercedes — I can’t believe I’m saying this — is the better bet.

You struggle with this E-class to find anything that jars or annoys, but don’t worry. I’ve come up with something.

The fuel gauge is a series of digital bars, and I’m sorry but that’s rubbish. Fuel gauges should always be analogue so, by moving your head, you can convince yourself that there’s more in the tank than the needle would have you believe.

When you’re down to one digital bar you don’t know when it’ll go out. And that means I’d spend my life spluttering to a halt at the side of the road.

In fact I did. But it’s okay. I had my iPod with me. So I just sat waiting for fresh supplies of fuel while listening, on my own, to Jackson Browne singing Running on Empty.

I think that one’s a bit embarrassing too.

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