A long while back we installed the GP rear diffuser on SilverBeast. This improves the aerodynamics under the car and gives a more appealing look to the rear of the car either side of the exhaust.

It is because of this visual improvement, giving the car a beefier, sportier and more purposeful look, that this modification has been so popular.

However, without the engine under tray from the GP2  also being fitted then this modification in truth is purely aesthetic and gives no aerodynamic benefit at all. However, match it to the engine undertray and you have the same aerodynamic set up under the car as the GP 2 and this does make a difference.

Above is what SiverBeast looked like before the engine under tray was added and below is how it looks with it installed.

Yep no difference can be seen at all unless you crawl under the engine bay. This is why there has been a much lower take up on having the under tray fitted, compared to take up of the rear diffuser as a modification.

In terms of aerodynamic handling I doubt I drive the car hard enough to notice much difference. That is the honest answer but having spotted other signifcant differences, I don’t doubt that is does work in making improvements in the handling.

Two things we have noticed. First, the noise. This car not quiet and a lot of the noise comes from road noise under the car. The car is a lot noisier than an R56. You had to either talk or listen to the radio but not both. Now, with the undertray fitted, you can have the radio on and still be able to talk. Now we can hear the engine more which is a much better noise than the road noise that dominated before. Also we can pick up the windscreen windnoise which again was drowned out by the road noise from below. For these benefits alone we feel the under tray has been a worthwhile benefit.

Secondly, we have a better fuel consumption. We are now getting an extra 2 to 3 miles per gallon on what we got before. I kid you not here.

So there you have it the GP2 under tray. It works!