Although Porsche says that 75% of the parts are "new or modified", the Macan - second and smaller of the SUVs made by a company which formerly specialised in building sports cars - shares its essential platform with that of the Audi Q5.
This is a technical point which probably won't matter to more than a few dozen of the Macan's potential buyers, and there would be no reason to give it more than a passing reference if it didn't lead neatly to another thing the two cars share.
The first Q5 I ever drove was fitted with large wheels and low-profile tyres. The second, far more sensibly equipped, was about forty-seven times better. I have no reason to believe that this was a coincidence.
The same thing seems to apply to the Macan S. As standard, it has 18" wheels with 60-section tyres at the front and 55s at the rear. I haven't yet driven one in that form, though, because Porsche GB has very few Macans on its press fleet and they are all handsomely bestowed with optional extras - including, in this case, 20" wheels, 45-section front tyres and 40-section rears.
I would be interested in hearing the views of a Porsche engineer on this, preferably after he or she has forgotten that you're meant to wear the corporate mask when talking to journalists and started giving honest opinions. (In my experience it rarely takes longer than two minutes for an engineer to get to this stage.)
I suspect the engineer would at some point make it clear that the suspension of the Macan S was set up to work with the 18" wheels, and that fitting 20s is an act of vandalism on the part of the marketing team. Not having had such a conversation, I can at least say that it certainly feels like it.
In this form the Macan S feels horrible on anything but the very smoothest of roads, and as you know we don't have many of those in this country. The short and therefore stiff tyre sidewalls are unable to absorb shocks which are instead transferred to suspension which wasn't designed to deal with them, and the result is an awful ride and questionable behaviour over bumps.
I'm no fan of such large wheels as a general rule, but they are not the source of the problem. Other Porsches run on 20s and behave very well because 20s are what they were designed to have. The Macan S wasn't, and doesn't.
Spending £785 on the optional Porsche Active Suspension Management as fitted to the test car doesn't help. PASM has three stages of damping - Comfort, Sport and Sport Plus - and with those wheels the Macan S doesn't ride or handle well in any of them. Please, please, if driving dynamics mean anything to you at all, save yourself £1457, forget about the 20s and stick with the 18s.
"There must be something you like about it," said an unhappy-looking Porsche person.
Oh, yes. There is a lot to admire here. The combination of a lusty 335bhp three-litre six-cylinder engine and seven-speed PDK semi-automatic gearbox is very sweet. And I like the steering for its superbly smooth action, though I accept that some people might think it's a little too heavy.
The front seats of the test car were absolutely brilliant - among the very best, in fact, that I have ever experienced. One slight problem with them is that they are extra-cost options, costing £1214 for the pair, and another is that there is no room underneath them for the feet of rear passengers, which drastically limits the size of person who could comfortably sit there. (A suggestion that this helps distinguish the Macan from the larger Cayenne was treated with some disdain.)
The luggage compartment offers 500 litres of space with the rear seats up and 1500 with them down - not quite as much as the Q5 but a decent volume all the same.
There have already been references in this review to optional extras. It's a difficult subject to avoid with Porsche, since in most cases there are a great many of them. Some are curiously priced - I'm not sure, for example, why both the carbon side blades and the 14-speaker Bose surround sound audio system both cost £801 when a more conventional figure might have been chosen.
And there's the usual question of why some things are optional at all. Cruise control costs £348, a reversing camera £332, Bluetooth connectivity £271 and front-seat heating £259, and I can't help thinking that if I'm being asked to pay more than £40,000 for a car I should get these things without asking for them. Then again, I'm not a natural Porsche customer (though I'd have a Cayman tomorrow if I could) so maybe I'm missing a point about the amount you spend being directly proportional to your sense of self-worth.
(Final note: the Macan S gets four stars here on the basis of what I imagine it would be like on the standard wheels. On these ones, it barely qualifies for two.)