Ideal engine layouts for a fun sports car? No such thing as the perfect one, of course, as for every argument in favour of one someone can come back with a counterpoint against it. Furthermore, if you start quoting the motoring rule books at people, someone will always come back with an exception: your rear-engined car might handle like a sack of potatoes, thanks to its swing axle rear suspension, but my rear-engined car can lap the Nurburgring in under seven minutes.
What you need is a garage large enough to contain an example of each. As the weather's been good, I think we should take a moment (presumably not a polar one) and find ourselves an open-top car, and, with the help of our classifieds, build up that garage, being careful to keep everything cheap.
Where to start, then? Easy. For balls-out decadence, for extrovert pleasure, for sensual gratification and for sheer driving satisfaction there's a lot to be said for a mid-engined, rear-wheel drive layout. Even here I should add I'm thinking of a rear mid-engined layout, although there's nothing wrong, and quite a lot right, with a front mid-engined layout - it did just fine for the S2000, or the LFA, or even Bristol, after all.
Having established that, then, what size is our ideal fun car? Small is the word. If you've ever driven a mid-engined supercar of any sort, from Miura to 488 Pista, you will know that caution can impede enthusiasm as sure as blindspots can lead to accidents, as can the prospect of expensive repairs; this fun car needs to be small, and preferably easily repairable.
It follows it should be cheap to buy, too, and if it's small and lightweight it won't need a V12 to push it along - a 698cc turbocharged triple should do it nicely. The tiny Smart Roadster is still beloved by a coterie of enthusiasts for good reason - it might only have 80hp, and it might have a dim-witted automated manual gearbox, but its fun factor is sky-high. Indeed the experience of driving the thing actually overrides the obvious shortcomings inherent in the car's underpinnings: its steering is too slow and the handling can be a little wayward, after all, but if it's good enough for Gordon Murray - and it is, he loves his - it's probably good enough for us too. This one we found is worth a look at £3995.
Ancient and rarer than hen's teeth the glorious Fiat X1/9 outdates the Smart by a couple of hundred years. However, its mid-engined, rear-wheel-drive layout was a delight. The car was structurally remarkably strong, the better to cope with its removable Targa roof panel and the car's rollover capabilities. With a lively Lampredi SOHC engine borrowed from the impressive 128 saloon the X1/9 was just about fast enough in a straight line, in its day, and more than fast enough around the corners, with prodigious roadholding that really belied its modest tyres and handling that was infinitely adjustable. Now, alas, the ravages of time mean that X1/9s are rare and expensive, but here we've found one for £7995, a startling amount but one that is I guess no more frightening than those charged for some of its much less able contemporaries.
So you want something on a similar level but with a classic front-engine, rear-wheel-drive set up? Can't argue with a Mazda MX-5, and, if we're being honest, you can't logically argue with the statement that the newer ones are generally better than the older ones, despite their lightweight charms. The latest droop-snoot dinky toy is a fantastically good thing, and the previous Mk3 was pretty good fun, too. This 2007 low-mileage example of the third-gen car is up for just under £4k, making it something of a bargain and unfeasibly tempting. True, no one ever died of pleasure sitting in a Mazda, but the simplicity of the MX-5's driving experience - chuck it, boot it, catch it - will establish it as a legend long after the last petrol-engined car has rolled off the conveyor belt.
How about something with a front-engine, front-wheel drive layout? The Fiat Barchetta will do, for starters, providing you have no objection to left-hand drive. It might worry purists by being a Punto underneath but it had just enough brio and more than enough panache to see off its critics. This one is up for a mere £3k, and provided you adhere to all the usual rules inherent in buying an ancient Fiat it strikes me as a potential funster supreme. And don't worry, it resists understeer far better than its origins would have you believe. True, it's not as adaptable as some of its RWD rivals, but there's real pleasure to be had in its fluidity and composure through the bends.
However, if you prefer right-hand drive, and you want to stick with the Italian, why not try this Alfa Romeo GTV Spider? With steering at 2.2 turns lock to lock things start off well, and despite a few shakes from its rather loose scuttle it handles like a honey, blissfully agile and surprisingly neutral, and in 2.0-litre form probably even better balanced than the sonorous V6 version.
For a bit of added security, what about a front-engined, four-wheel-drive car? The Audi TT Quattro Roadster has a startling breadth of abilities and makes perfect sense, and if the V6 version strikes a chord on paper the cheaper to run 1.8T, with its 225hp and 0 to 60mph in 6.7 seconds potential, is perhaps the ideal tonic. A well-kept 2004 version with a low mileage looks good value at £4995.
The TT's intelligent Haldex coupling feeds power to the rear wheels only in extremis so the TT is a front-driver in most conditions, which means it's grippy and generally predictable. Don't think it dull, though, as it'll wag and twitch with the best of them on a fast corner, if you want it to, but what it offers that others can't is added security, especially if the roads be wet.
Okay. Finally. Where do we go for a reasonably priced, rear-engined, rear-wheel drive open-top sports car? Zuffenhausen, of course, if we're allowed to spend a little more, for perhaps the most perfect example of development over design since the Rolls-Royce motor car: the Porsche 911. To keep this cheap, let's pick out this prime 1998 996 Porsche 911 Carrera Cabriolet, up for just £11,995 in the classifieds.
You can't argue with a top speed of 174mph and a 0 to 60mph sprint time of 5.4 seconds, and nor can you argue with the immense grip that a properly shod 911 can provide, even one with a soft top. You can balance this one on the throttle or the steering, and whatever your thoughts on the merits or otherwise of rear-engined cars suffice it to say that modern 911s seem to work, and work well - think of it as an example of doing the wrong thing the right way, rather than the right thing the wrong way.
And on this final point I shall merely link back to my opening paragraph - there are always exceptions to every rule, and if you don't like the rules you must ignore them all. Including that one.