It was with its 55-badged generation of tuned factory Mercedes models that the growth spurt that has taken AMG to the brink of launching its own hypercar started. Having been known for a handful of ultra-rare-groove saloons throughout the 1980s and 1990s, the company showed us the SL55 in 2002, and followed it with supercharged versions of the contemporary E-Class, S-Class and CL coupé. CL55s tend to be the most affordable of the lot today, and they pack a hulking 493bhp.
Merc’s famous M113K supercharged V8s have been known to develop cooling problems, so check for a healthy radiator (and no coolant leaking into the transmission lubricant) in any car you’re considering.
How many cars bludgeon their way through the 400bhp barrier for this kind of budget quite like a Porsche Cayenne Turbo? Precisely none. The original offensively fast luxury SUV was also the only big Porsche its maker built through the early part of the last decade. It had 450bhp in 2002, back when the 911 Turbo (996) had only that much.
You won’t have to do anything special to achieve our £10,000 target, but do check that it’s not about to cost you as much again in repair bills. Be wary of misfiring engines and jerky transmissions.
The BMW Motorsport version of the E39 5 Series was the first truly modern M5. Shunning the straight-six engines that had served its predecessors and adopting a 4.9-litre V8 instead put the performance four-door into a new league in terms of power and speed in 1998.
The car ‘only’ had 394bhp officially, but another 50 horses can be teased out fairly cheaply with an ECU reflash and some induction and exhaust upgrades.
You’d have to accept a little bit of risk on reliability as part of the deal in buying a used example of the original, Discovery-based L320 Range Rover Sport Supercharged. Most problems you may encounter will be minor electrical niggles, though. The major issues are limited to suspension compressor issues and steering vibration complaints.
Get a healthy later model and you’ll be able to increase power from the factory-spec 385bhp to more than 400 via a quick reflash of the ECU, making this a sub-7.0sec 0-62mph car.
You weren’t expecting to read about a Lexus hybrid in this section, but this one combines combustion and electric power to produce 438bhp. The LS600h is comfier and more spacious than anything else we’ve touched on, and is unlikely to trouble you with faults. Toys include a DVD changer and rear-seat entertainment screens, heated seats and more. A slice of dependable 400bhp luxury and on-budget... almost.
Original supercharged XKR coupés are now well into that delectable ‘old Jag’ territory as used cars: too nice to be so cheap and too cheap not to be sorely temping.
This car hailed from a time before the design rejuvenation of the Jaguar brand; the direct inf luence of the likes of the C- and D-Type could still be seen in its fuselage-style look. But under the bonnet, the car wasn’t so retro. Later 4.2-litre examples left the factory with 390bhp and a six-speed ZF automatic gearbox.
Chevrolet’s small block V8 is such a time-honoured route to maximum bang for your buck that we had to have one in here somewhere. For this money, you can forget Chevy Camaros or Corvettes, but the earliest Vauxhall-badged Holden Monaro CV8s are affordable.
And while the 5.7-litre lump only provides 335bhp, a company such a Monkfish Performance could turn into it into a genuine 400bhp car when given a small four-figure budget to work with. Good, cheap early Monaros are getting harder to find. Don’t buy a car with body damage; panels can be ruinously expense if you have to source them from down under.
Twin turbos, four-wheel drive and as quick as you like. More’s the pity, then, that Nissan Skyline GTRs of the R33 generation are quite rare in the UK. Still, if you’re keen to develop your 400bhp for £10k option via the tuning route, it is worth seeking one out. The car’s six-cylinder 2.5-litre turbo engine came with 280bhp as standard, but experts say they can be massaged to 400bhp without the need to make major revisions to gearbox or fuelling system. There are plenty of places that tune ’em.
At the turn of the last decade, Audi’s Quattro GmbH factory tuning department wasn’t taking many prisoners. The RS6 had a monstrous twin-turbo V10 engine and even its little brother, this S6, had ten cylinders. The detuned Lamborghini engine produced 429bhp and made the car good for 60mph in just 5.2sec. Service parts are pricey, so be wary of cars with missing or incomplete histories. Ignition coil packs can cause engine problems.
An alternative, quietly cultured bit of American muscle with a 6.1-litre ‘hemi’ V8 producing 425bhp ‘right out of the box’ – and good for 60mph in less than 5.0sec. The car is rare in this country, and not as great to drive as other super-saloons, but the performance can’t be questioned. Look out for warped brake discs; listen for knocking from the front suspension. Otherwise, very reliable.
This piece really doesn’t need much explanation beyond the headline.
The very fact that there’s one way to put a 400bhp car on the driveway for less money than most families spend on a supermini deserves a cheer – and we’re bringing you 10 of the best options.
Some of these cars should qualify straight away, others with a bit of light tinkering and one or two with some not-so-light tuning.