bluestuff ngx are track only, ive used yellowstuff on road and track and they have been great. fantastic value for money.
The ebc website tells you about the different type of pads. The yellows are about as low rated as i would venture in their range.
Ive got a set of bluestuff ngx waiting to go on to review for a trader on here. Will be doing a logged report from fitting to running on road and track.