Traffic officers from West Midlands Police stopped the bright green BMW M3 Estate on Dartmouth Middleway in Birmingham on November 15 last year.
Their suspicions were raised due to the fact that BMW has never made an estate version of the car.
It was seized for inspection and they later found the vehicle, which had been showcased at a car show in Germany, was a "death-trap" made from at least four cars.
Parts were traced to one BMW M3 stolen on September 30, 2019 from a car showroom in All Saints, Wolverhampton, and another M3 stolen on March 20, 2018, in Sutton Coldfield.
Two estate vehicles had been used to create the main body and the panoramic roof. The car has now been shredded at a specialist scrapyard with police urging people to look for "tell-tale signs" that can help them avoid buying a car like this.
Pc Mark Wheaver, from the Central Motorway Police Group, said: “This should act as a striking reminder that cars may not be what they seem. You might think you’re buying a bargain but it could be a death-trap that cost your life as well as thousands of pounds.
“This BMW looked great on the outside, you can’t fault the paint job, but scratch beneath the veneer and it was just tag welded and structurally unsafe. A coat of paint won’t save your life in a collision.
“Whoever had bodged this car together had gone to significant lengths to try and hide its true identity. Numbers had been ground off and stickers removed but we have expert vehicle examiners who use techniques to overcome these obstacles.
“Our Central Motorway Police Group is training increasing numbers of officers to examine cars we stop to identify if they are cloned or feature stolen parts.
“They are patrolling the region, stopping and checking any modified vehicles for insurance and stolen parts, and any we find will face the same fate as this M3 show car.”
Specialist vehicle examiner Boyd Howells said the force has had to seize countless cars from people who thought they’d bagged a bargain – but in reality had paid criminals for illegal vehicles made using stolen parts.
He said: “These buyers don’t get their money back. We seize the vehicle as it’s illegal and unsafe – and I’m pretty sure criminal gangs selling such vehicles don’t offer compensation.
“That’s why it’s really important car buyers are switched on to the signs a car could be dodgy. One of the most important messages to still remember is ‘if it looks too good to be true, it probably is’. Ask yourself why is such a good looking car such an attractive price?
"I recommend buying cars from main dealers or approved used car stockists. But if you are buying from an independent dealer pay a deposit or minimum of £100 on a credit card as it offers protection. If they refuse credit cards that should be a red flag.
"Always inspect the car first – and if you’re not great with cars take along a friend who is, perhaps your regular mechanic. You could also pay for an HPI check against the vehicle but these should only ever be used as a guide and are not advertised as 100 per cent accurate."
There is no evidence to suggest the car’s owner was involved in the car thefts, a spokesman for the force said.