Mercedes team principal Ross Brawn says there is so much opposition to the team's DRS system because it is difficult to integrate in to existing car designs.

13807 - 'Cheap' DRS tough to copy - Brawn

The FIA appears to have clarified on numerous occasions that it sees the system as legal, but Red Bull and Lotus especially continue to ask the governing body to revisit the issue. Because the air flow is channelled from the rear wing back to the front wing the whole structure needs to pass along the length of the car, and Brawn said the difficulty in packaging it has caused teams to mount a more sustained challenge.

"The opposition is so fierce (because) there's a recognition it's quite difficult to do," Brawn said. "It's a very simple, cheap system, but not so easy to implement if you haven't integrated it into your car. This is at the heart of the frustration of some of our opponents. If someone could put it on their car easily, I promise you we wouldn't be having these discussions."

With the FIA expected to revisit the issue in China, Brawn said he hoped the governing body would retain its so far unchanged stance.

"We would obviously be extremely disappointed if someone was to take a different view. The FIA have been fairly consistent over their position so we have faith that they'll maintain that consistency."