I have uprated front EBC grooved disc which are about 2 years old but my car has only done about 3k miles in those two years and recently put Mintex 1166 on the front.
While tracking last weekend I found braking at high speed i was getting a lot of judder from the brakes. On the road they feel great !

Do you think think its time to change the disc???

 

Maybe it was because on the track the discs were getting red hot under heavy braking causing the judder either that or one of your callipers could be sticking mate.

 

Cheers bud I will get the callipers checked before I make a decision on the disc...........