Vehicle chippers, or engine management specialists as they prefer to be called, claim that they can significantly boost a vehicle's power output and improve economy without compromising its capabilities or damaging components such as turbo chargers.
And, they say, it is not boy racers but rather businessmen, reps and professional drivers who are proving to be their best customers.
But whatever their social status, most of them appear to be willing to gamble away their insurance cover by refusing to inform their brokers of the modification, despite a legal obligation to do so.
According to Superchips, one of the world's largest chipping companies, by reprogramming a vehicle's electronic control unit (ECU) - a set of silicon chips that monitor and control engine output and efficiency - power and torque can be substantially increased.
"Manufacturers have to assume that their customers are not going to look after their cars," explains Barrie Manders, managing director of McNamara's Carburettor and Injection Centre, the Irish agent for Superchips. "They have to assume that the motorists are not going to get their car serviced, that they will put the wrong fuel in and that they will never check the oil."
As a result, manufacturers set up the ECU to under-use an engine's capabilities and thus extend the life of components. But, argues Manders, for people who maintain their vehicles correctly there is no need for such a safety margin.
Recognising this, and the fact that independent chippers are making money from their technology, some manufacturers offer their own reprogramming services. For example, Mitsubishi in Ireland offers such a facility as an aftersales service to buyers of its L200 pick-up; Subaru is happy for Prodrive to replace the chip in its Impreza STi to help increase power output from 262 to 300 bhp; and BMW will tune its Mini Cooper S up to the 200 bhp Cooper Works specification by ECU remapping.
But as Clare O'Neill, marketing manager at BMW Group Ireland, warns, it's only its franchised dealers who are authorised to do the work. "If a customer gets the work done elsewhere, their car would not be covered under BMW's warranty," she says.
Despite these warranty concerns, it is estimated that some 500 Irish motorists every year go to independent chippers. This is a conservative figure, says Brian Hughes, underwriting manager for AXA. When one considers that it costs as little as €400 to increase power output - around 30 bhp on a 1.9-litre turbocharged diesel engine - and improve economy, he is probably right.
One motorist who took his new diesel-powered €55,000 Mercedes to be chipped as soon as he bought it, sings its praises: "The common-rail technology was already very impressive but, with the chip, the car was instantly more drivable. The power was available at much lower down the rev range and I also noticed a huge improvement in fuel economy. I can now get 38 mpg where before I was getting 31.8 mpg."
However, this Dublin-based car enthusiast neglected to inform his garage of the modification - and therefore did not want to be named in case he later makes a warranty claim.
Herein lies the problem for manufacturers: even their own authorised diagnostic centres find it very difficult to determine whether a car's ECU has been remapped.
As Denis McSweeney, marketing manager of Ford in Ireland, explains, those going to independent chippers are running major risks. As well as invalidating a warranty and increasing the chance of mechanical problems, such as engine overheating and turbo damage, these modifications "could also lead to premature deterioration of other parts" which would lead to serious problems at re-sale and trade-in time.
The mechanical risks increase relative to the bhp. Some independent garages advertise power increases to as much as 1,000 bhp, but the accepted rule is that an engine's output should not be boosted by more than 30 per cent.
As the boy racers' bible, Max Power, warns, by going beyond this threshold on a turbo-charged engine, major modifications are needed to other components to cope with increased stresses. "It gets expensive," the lads' mag bluntly states.
However, it's in another area that those who get vehicles chipped are taking the most worrying risks. Regardless of whether they are boy racers or professional drivers, it seems they are all of a similar mindset when it comes to insurance.
AXA says that only one of its customers has ever come forward after having his car chipped - and, when told of the premium increase, declined to renew his policy. Every motorist who has a vehicle's power increased is obliged to inform his (or her) insurance company. However, with no visible signs that a car has been chipped, insurance companies must rely on their customers' integrity - something which is clearly lacking.
As Hughes says: "It's a matter of probability that we have customers who have had cars chipped, but we have only ever had one person admit it" . . . worrying news from the underwriter of the country's largest private car insurer.
Indeed, our Mercedes driver did not want to be named for another reason: he is one of those who declined to inform his insurance company of the modification. As a result, he has invalidated his policy and will find himself in serious difficulties if he has an accident.
"If we discover a car has been chipped and we were not informed, we would take a very dim view of the situation," says Hughes. "And, if the car was damaged, even under a comprehensive policy, we would not pay out."