Fiat Chrysler CEO Sergio Marchionne has weighed in on the continuing Apple Car rumors. In an interview with Reuters at the Geneva auto show, the executive said Apple should think twice before jumping into making cars. He said automobiles are a ‘complex business’ and it makes more sense for Apple to partner with an existing car manufacturer than do everything itself. The exec felt so strongly about this, he described it as an illness to want make cars independently.

He believes that existing companies have enough spare production to accommodate Apple’s needs. Obviously, Fiat Chrysler would prefer if Apple took a more backseat approach to automobiles. Current reports indicate Project Titan continues to progress despite some bumps in the road with executives leaving the company.

At Apple’s investor call, Tim Cook likened the car project to Christmas, saying that it will ‘be Christmas Eve for a while’ — the rumor mill is currently suggesting a 2020 launch for Apple Car, so it’s still a way off. Following Apple Watch, it is thought the car will be Apple’s next major new product category.