Since enforcement of illegal street racing has been stepped up, mechanics say the modifying business is down and some clients even want changes undone.
Ban bites deep for men who add grunt
The warehouse shed shakes as Humaid Al Malek revs his modified Skyline R33, a 1,200-horsepower drag racer.
From a standing start, the car can cover 400 metres in 9.2 seconds. This is too slow for Mr Al Malek. He wants to do it in seven.
An Emirati with a quiet manner, Mr Al Malek gave up his job as an Adnoc mechanic to open the Japanese Performance Garage in Ras Al Khaimah with his brother Qais, 32.
While his business has dropped by half since police began their clampdown on illegal drag races in 2008, he says mechanics who know the power of their creations support tighter regulations.
"If somebody goes outside and makes a problem and it's noisy, the police should do something," says Mr Al Malek, a drag racer. "You should care about other people."
He now caters only for "brothers, cousins and friends", but his fame has earned him many friends.
Racing cars worth millions are kept in his warehouse, hidden in a gritty maze of dirt roads in downtown RAK.
"He doesn't need to advertise," says one admirer who has come to gaze at the enormous engines. "His name is famous."
Each afternoon Mr Al Malek, 31, trades his kandura for a Batman T-shirt and gets his hands greasy.
Customers typically pay him between Dh70,000 and Dh90,000 to strip their vehicles and fit them with turbochargers, superchargers and exhaust headers.
Some cars are fitted with a tyre on the rear bumper to protect them from the ground when the car rears on its back tyres, and many are given a solid body cover to keep them as light as possible.
Those who cannot afford the makeover fake it. They sometimes hit their exhaust pipe with a screwdriver or hammer so that it cracks. Sure, it will be broken, but it will have that roar.
But those who have their cars modified will then spend thousands to temporarily tone down their car so it will pass inspection.
Modified cars can also be fitted with silencers to muffle the noise. But some drivers take these silencers out on Thursday nights as they cruise down the Corniche.
Mr Al Malek says his cars are only modified for people who race at authorised clubs.
"Just for the club," he insists. "Nobody goes outside on the street."
Hassan bin Abboud, a Fujairah racer who collected his modified Skyline R32 on Sunday, says new regulations will not stop him from driving it "in the streets of all of the emirates".
The R32 is the favourite of his six cars and will go for its first spin this Thursday, on the Fujairah Corniche.
"I will feel like I am in the sky," says Mr bin Abboud, 26.
He has a scanner fixed to his car that can detect police speed radars and help him to avoid fines.
Trying to stop people modifying their cars is unrealistic, says Ahmed, the owner of several modified luxury cars, one of which is a Porsche he souped up for his sister.
"We go out in the middle of nowhere to race and have fun," the Emirati says. "Not everyone who modifies their car is reckless and irresponsible. But to get anywhere, we have to use the public roads for a bit to get to those isolated places.
"Those who cause problems and are dangerous should be stopped by the police, especially those who drive like crazy on small residential roads to show off to friends and neighbours. Those are the worst."
With the latest warnings from police, Ahmed is seeking different ways of transporting the cars to places where he and his brothers can race.
"It is not easy to just transport it," he says. "It costs money and time each time you want to take your modified car out."
Moosa Swaidan, who owns the Panda Performance Dubai garage, which specialises in modifications, says the new rules are hurting business.
"I have had about five clients from Abu Dhabi and Sharjah in just a week asking us to remove all the modifications done on their cars," he says.
His garage uses parts and equipment that meet international standards of safety and emission levels - standards he says are not met by many cars and motorcycles that come straight from the factory.
"A Lamborghini and Harley-Davidson from the factory make more noise and release more emissions than any of our modified cars or motorcycles," he says.
"What is going to be done about that? I doubt they can stop Lamborghinis and Harley-Davidsons from being bought and driven on the roads here."
Mr Swaidan believes only those who drive recklessly and illegally should be targeted, "not everyone with a modified car".
He is working with a safety committee at the Roads and Transport Authority to try to get a permit for making modifications that would be within the authority's safety guidelines at his garage.
If he can do so, Mr Swaidan says, "It would help make things clear for everyone involved."