Last week I had an interesting chat with a reader who was thinking of swapping his Jaguar XF for a new Mercedes E350 CDI.

He’d owned a series of previous-generation E-Class models and was ‘regretting’ selling his last of the line example.

The essence of the problem with the XF was that it was a bit ‘too harsh’ for everyday use, even though he’d had the dealer swap the standard 19in wheels for 18 inchers. Our reader was missing the way a Mercedes can just ‘pootle’ around the place.

As an aside, he told me that his local Jaguar dealer (in a relatively affluent of the North West) was a bit wary of the new XJ. ‘A bit too big for the sort of people who might buy it – the sort of car which needs a chauffeur.’

I guess these older buyers wouldn’t much like the car’s very focused sporting dynamics either.

From our conversation, I’d guess our reader was probably around retirement age, like a lot of Jaguar owners. And it struck me just how risky it must be for Jaguar to try and suck in a whole new customer base while running the risk of alienating loyal buyers.

However, there’s no doubt that’s just what Jaguar has done by focusing on ‘beautiful fast cars’ that are rather closer to Maserati than Mercedes.

For a company that wants to entice a ‘new Jag generation’ (a great catchline but one originally applied to the whole unsuitable X-Type) shows the complexity of having ‘the wrong kind of customers’.

Before General Motors dumped Saab, company product czar Bob Lutz told us there ‘just weren’t enough professors with leather elbow patches’ for the Swedes to prosper.

In the US, Saabs were indeed traditionally driven by East Coast liberals and intellectuals but GM regretted not being able to pull in another, rather more populous, type of customer.

Modernity is essential for carmakers. Most people, no matter what their age, want to buy a ‘modern’ car. However, it’s easy to get it wrong as the Rover 75’s ‘modernist Edwardianism’ and Renault’s recent avant-gardism has shown.

If the sharp-suited XF, XK and new XJ – which will all sell in relative modest numbers by global standards - set the scene for new Jaguar, it means that the company’s upcoming roadster and entry-level road car have to be judged perfectly to appeal to younger drivers.

Shifting your typical customer to someone in their late 40s might mean losing your older buyers altogether.

The risks for Jaguar in trying to shift its customer base are as clear as they are potentially fatal.