Flipping 'eck, Tucker! It seems like only yesterday that we sat here in short trousers enthusing about road car engines that could hit the magic 100hp per litre mark. We would rhapsodise in words poetic about the technological wonders that emerged from the factories of Honda and Ferrari and the like, salivating wildly over the S2000 or 360 CS or whatever. And what made them seem so otherworldly to us at the time was that most, if not all, of these highly tuned honeys were naturally aspirated, remember.
Motorbike engines were even better, of course, and reached such dizzying heights even earlier, largely due to them being unshackled from some of the inevitable emissions and longevity constraints. But it was the rise in popularity of forced induction that really upped the ante, with 100hp per litre then becoming increasingly common in road car engines. Now, you can have your twin-turboed 5.0 V8 Koenigsegg Agera RS with 232hp per litre, for example. However, if you like the idea of a highly tuned engine but want a more practical and affordable proposition, you could always try a Mercedes-Benz hatchback.
When the A45 AMG was launched in 2014 it blitzed its way to the top of the hot hatch horsepower tree with an output of 360hp, all from a relatively weeny 2.0-litre turbocharged four-pot. Subsequent revisions (to keep it one step ahead of Audi's RS3, mostly) saw that power rise to 376hp at a 6,000rpm, and if you think it might be deficient on the torque front think again: it also produced 332lb ft at just 2,250rpm.
That also worked out at 188hp per litre, at the time something rather mind-boggling for a production four-cylinder engine, especially one in a five-door hatchback. On the road it was, not surprisingly, staggeringly quick, with 0 to 62mph coming up in just 4.6 seconds. Its power was accessible, too, and it sent its oomph to all four wheels via a seven-speed dual-clutch automatic transmission and a 4Matic four-wheel drive system. It was normally front-wheel drive, apportioning power - up to a maximum of 50 per cent - to the rear wheels only once the fronts began to lose traction. It had grip, go and gumption, but it was heavy and as stiff as a board and some felt it lacked character: its engine note was especially disappointing.
It was expensive, too, but such is its notoriety it continues to hold on to its value rather well. However, it's now possible to get one for under another magic barrier, the £30k one, as witnessed by this example we found in the classifieds. This 2015 car is up for £27,500, has just 16,000 miles on the clock and comes with a full service history. It also features a year's MOT and a six-month warranty, too. Expensive still, admittedly, but it's earned its place in the hot hatch hall of fame, and as a curious alternative to a Golf GTI or Focus RS it could be worth a punt.
SPECIFICATION - MERCEDES-BENZ A45 AMG
Engine: 1,991cc, 4-cyl turbo
Transmission: 7-speed dual-clutch auto, four-wheel drive
Power (hp): 360@6,000rpm
Torque (lb ft): 332@2,500rpm
First registered: 2015
Recorded mileage: 16,000
Price new: £41,875
Yours for: £27,500