I have just discovered a new cool feature on X351 dash as I am watching some Youtube videos . Here's the link to the video

Jaguar XJ 5.0 (470hp) S/C Long 0-180 km\h - YouTube

So, what I say you go 40 km/h and acclerate and at the same time your speedometer shows and lights up area 60-80 km/h . Same goes for when speed up 120 km/h and speedometer lights up 140-160 km/h area
WOW, that's a cool stuff but beware such high speeds lol

 

Isnt that just the flashlight effect.

 

over here they call it the Torchlight effect, you can turn it on or off in the menu system that comes up in the drivers dashboard control list on the right hand dial.

 

Thanks for your replies , I have noticed that your RPM gauge also lights up besides speedometer . This is really a cool light effect