Sebastien Ogier is driving the test car on Wednesday and Thursday, with teammate Elfyn Evans already having reported his findings after driving the car in Finland earlier this week.

The main element of the new aero set-up is the rear wing, which is aimed at further improving the stability and grip from the rear of the car is one of the defending champion squad's aims for the second half of the season and team principal Malcolm Wilson is confident the test will provide the required results.

Wilson told Motorsport.com: "We've got some parts coming for Finland and obviously we hope they're going to be an improvement.

"For us it's mainly aero. Trust me, you'll definitely notice the difference with what we've got on the car.

"The work on the rear wing was done in the wind tunnel in Charlotte when the car was out there [after Rally Mexico], the guys have been working hard on it since then.

"It's going to be a big change at the rear for us."

The decision on whether to implement the change in time for the Jyvaskyla-based event, which starts on July 26, will be taken later this week.

The aerodynamic balance of a World Rally Car is never more heavily tested than in the Finnish forests, on the fastest WRC round of the season.

The route for this month's Rally Finland is expected to be slower than in previous years, courtesy of the use of narrower and more technical stages, but it's still likely to be the fastest rally of the year.