6 Unconventional Sleepers For Every Budget

1. Under £20,000 - Audi S6 (C6 V10)

If you’re looking for a fast and comfortable vehicle that has space for your friends and their skiing gear (first world problems) then look no further than the Audi S6 (C6). Released back in 2006, the S6 is potentially the most understated performance car of all time, blending middle-of-the-road Audi looks with a Lamborghini-derived 5.2-litre V10. Well, kinda.

The engine was in fact based on the exotic Lamborghini unit, but the Audi motor featured a series of changes such as a modified cylinder block, new pistons, a different crankshaft and new camshafts. The engine also received Audi’s direct injection system (FSI), requiring changes to the induction and exhaust system. So it wasn’t exactly an Italian-powered beast, but these changes were necessary to ensure the reliability Audi required.

The S6 is a fairly heavy beast weighing in at 1920kg, but the V10’s 429bhp and 398lb ft of torque help to disguise the mass by rocketing the Audi to 62mph in an impressive 5.3 seconds. With some light tuning we have no doubt that this would be a 200mph autobahn monster. For extra stealth points, we’d go for a black de-badged Avant like this one.

2. Under £15,000 - BMW E60 550i

The BMW E60 550i in countries like the United States is just ‘another car’. But in the UK where diesels dominate the mid-range sector, they’re incredibly rare beasts. In fact, there are only 15 550i M-Sports registered on UK roads.

With a 4.8-litre 362bhp V8 mated to a six-speed manual gearbox the 550i reaches 62mph in 5.3 seconds and goes on to a limited top speed of 155mph. When looking for a second hand bargain we would search for a well specced SE model (this one even happens to be bullet proof). The M-Sport is arguably better looking than the SE but the 18-inch alloy wheels and body kit are a bit too showy for proper sleeper potential. If you’re wanting full stealth make sure you get the badge delete, like this one here.

3. Under £10,000 - Rover 75 V8

This is potentially the most bonkers car on the list. Not because it’s incredibly fast or particularly outlandish, but because Rover decided to shoehorn a 4.6-litre, 256bhp Ford Modular V8 into one of the world’s most boring cars, and converting it to rear-wheel drive while they were at it. Released at the Geneva Motor Show in 2004 the V8 was created to show the world that MG Rover had great engineering expertise and that they could be viewed as a ‘premium brand’.

The car wasn’t a particularly engaging machine to drive thanks to a dim-witted automatic gearbox, lifeless steering and pathetic brakes, while soft and under damped suspension didn’t help matters. But then again, what do you expect from a Rover 75? It was never going to be a super-saloon. The related MG ZT 260 was firmer and ditched the slow auto for a manual gearbox, but with its aggressive bodywork and chrome accents it isn’t stealthy enough for our liking. We would take the 75 every time, and maybe ponder bolting on a supercharger….

4. Under £10,000 - Saab 9-3 Turbo X

The second-generation Saab 9-3 was an undervalued and under-appreciated car. Released in 2002, the 9-3 was an interesting alternative to the bland selection of BMWs, Mercedes and Audis. In various group tests of the time the 210bhp 2.0-litre turbocharged Aero came out ahead of its German rivals. Unfortunately, like most of the cars in Saab’s lineup, the mid-sized saloon suffered from GM’s neglect, receiving hardly any updates during its 10 years on the market. As a result it wasn’t long before the Swedish saloon was outshone by its other competitors.

Hoping to show what the Swedish automaker was still capable of, a range-topping 9-3 Turbo X was released in 2008. The car ditched the ageing 2.0-litre turbo for a 2.8-litre, 280bhp V6, which was mated to a six-speed manual (or optional automatic) gearbox. To handle the increased power the X also featured a Haldex all-wheel drive system (a first for the manufacturer) and an electronic limited-slip differential.

Making use of its increased four-wheel drive grip the 9-3 X could rocket from 0-62mph in 5.7 seconds and would go on to a top speed of 155mph - not bad for a platform that was nearing the end of its decade-long life span. Giving the car some added stealth, all Xs came in metallic black with matt titanium 19-inch wheels. Sitting on 10mm lower springs also gave the car some much needed aggression. Only 500 Turbo Xs made it to the UK (600 in the US) making them fairly rare. Therefore it can be difficult to find one for sale, but they tend to fall below £10,000, making them something of a bargain.

5. Under £5000 - Passat 3.2 4Motion W8

There are some cars that have no valid reason to exist. The Passat W8 is one of them. I mean, who really needs a family car with a 4.0-litre, 275bhp W8? The whole concept seems even more silly when you consider that machines like the 282bhp BMW 535d are quicker, more economical and more dynamically impressive.

But then again, there is something intrinsically cool about a car that exists just ‘because’. First released back in 2002, the Passat W8 cost an eye-watering £38,000. No surprise then that only 246 were sold in the UK. But when you consider the engineering that went into developing the car, it almost seems like a reasonable price.

The engine itself is a real showstopper. It’s basically two VR6 blocks (with a couple of cylinders missing) bolted together at 72 degrees. This construction allows for compact packaging and the basic design has been used to great success in a range of other VW Group vehicles, the most famous being Bugatti’s W16. At only 275bhp the engine should be pretty under stressed; just watch out for slipping clutches.

The four-wheel drive system helps to make this car a great winter daily and the interior is a pleasant space, full of high-quality leather, wood and/or aluminium. VW wanted this to be their entry level halo car so most examples will have had the whole options catalogue thrown at them. Due to the monster of an engine and high level of tech, servicing can be expensive, pushing the price of these Passats below £5000.

6. Under £5000 - Mazda 6 MPS

A Mazda 6 probably isn’t the first car you visualise when you think of a traditional sleeper. But the MPS more than deserves its place on the list, as it’s a real wolf in sheep’s clothing. Released in 2006, Mazda shocked the automotive world with its hot 6 variant. From the outside you’d never have guessed that the very standard looking saloon packed an advanced (for the time) four-wheel drive system and a turbocharged 2.3-litre 256bhp four-cylinder engine.

The four-wheel drive system is heavily front biased, sending only 50 per cent of drive to the rear when required, but this didn’t prevent the Mazda from winning various group tests and outshining rivals like the Vauxhall Vectra VXR upon its release. In a straight line the MPS was equally impressive, sprinting from 0-62mph in a rapid 6.6 seconds, continuing on to a 150mph top speed.

If you’ve always wanted a Subaru Impreza or Mitsubishi Evo but have been put off by their outlandish styling, the Mazda is a good second hand equivalent. It’s not going to be as dynamically accomplished, but you also don’t have to put up with the disapproving looks from other motorists. Prices have dropped in recent years and you can now find examples for under £5000.

So CTzens, these are a selection of our favourites, but we’d like to know what cars you consider to be ultimate sleepers. Let us know!