"Doing something that will stupidly increase the costs is not what we want to achieve," said Boullier. "But it's a competition and we can change the cars as much as we want.
"Within the regulations, I think engines should be frozen once every manufacturer has been able to develop their engines. If you disallow the competition, then this goes a against the spirit of the sport."
"They benefited from the fact that they did a very good job and they benefited from the fact that the regulations are locked with the engines being frozen," he added. "Most of the gains they have had come from the engine – and they will for a couple of years until everybody can match them in terms of development.
"This is what they are benefiting from and if you could unfreeze the engine regs, you will see some catch up."