Changed the bulbs in the dash to blue LEDs :)
greenlights_zpsf1caedee.jpg photo by JNEC693 | Photobucket
To this!!
bluelights_zps3ce394af.jpg photo by JNEC693 | Photobucket
Hmm.. im no td5 expert but it sounds similar to when the td5 packed up at work, listen to the fuel pump, if thats buzzing its on its way out and you will need to replace it.
If its not buzzing, then i have nooo idea
Dont forget that tyre diameter will play a part, if you got small tyres then your going to be giving it more stick when it comes to higher speed.
And obviously, bigger means less stick blah blah blah, hope people can see where im going with this.