Ferrari is reportedly contemplating blacklisting drivers who go too far in personalizing their cars after purchase as the luxury carmaker tries to find a balance between protecting its exclusivity and servicing a lucrative customization market.

The Italian carmaker is growing weary of its drivers' increasingly garish customization requests, and its CEO is keen to take steps to narrow the scope of its own color offering as a result.

Ferrari’s CEO Benedetto Vigna warned of the prospect of a growing number of “strange” Ferraris being unleashed on the roads, devaluing the brand.

“We have been thinking internally maybe to pre-define the (colour) combinations. We have to pay attention because we have to defend the values and the identity of the brand. We will not make a strange car, for sure,” Vigna told the Telegraph.

Ferrari grossed around €1.3 billion ($1.35 billion) from personalization last year, accounting for about a fifth of overall revenues. The carmaker would rather personalizations were made on their terms, though, and it has struggled to talk down some customers.

“There are some places in the world where they like to have a set menu. There are other places where they want à la carte and to be free to select what they want,” said Vigna.

On Ferrari’s earnings call on Tuesday, Vigna said carbon finishes were also an increasingly appealing personalization. 

The manufacturer isn’t planning to stop its style-policing of Ferraris once they roll off the lot, either. In addition to protecting the brand, Vigna said that he wanted to preserve the value of second-hand Ferraris, which are often traded in by owners for new models. 

The Telegraph reports this could include banning customers from ordering further cars from the company again if they go too far with their post-purchase customizations.

“There are some combinations that are not liked or loved by the second potential buyer,” said Vigna.

A representative for Ferrari didn’t immediately respond to a request for comment.

Carmakers double down on personalization

More than 90% of Ferraris ever made are still on the road, according to Ferrari pre-owned director Andrea Scioletti, so any customizations not in line with the carmaker’s vision are likely to leave long-lasting scars.

The Ferrari Approved program involves a detailed inspection and renovation of pre-owned Ferraris before they are sold to a new buyer, including exterior and interior pre-preparations. 

Ferrari’s reticence to give customers carte blanche to modify their cars as they wish throws up a quandary for a luxury sector that has been on an investment drive to improve its personalization capabilities.  

Bentley enjoyed revenues of nearly €3 billion ($3.1 billion), crediting “levels of personalization that we’ve never seen before” as customers spent hundreds of thousands of dollars each modifying their cars.

Luxury carmakers have pledged to double down on their ability to serve their superrich buyers’ quirky, expensive preferences, bringing more of this lavish spending in-house and away from third parties.

Jaguar Land Rover announced in January a £65 million ($81 million) investment at two of its sites to expand its paint capacity, which would allow drivers to paint their cart the same color as their private jet or yacht.

In the same month, Rolls Royce announced a £300 million ($376 million) investment in its U.K. Goodwood factory focused on bespoke models, allowing its global customers to “craft an entirely original motor car.”

This story was originally featured on Fortune.com