I've replaced the front stock rotors in my XR6T twice now with DBA T2's and a new set of Bendix Ultimates with each change and never had a problem with shuddering. (Still running the stock rotors on the rears, but with new Ultimate pads).
I think it is very important that the hub is smooth, clean and free of any rust build up before installing new rotors. I feel a lot of brake places don't take the time to do this properly IMO.
The aggressive abrasive nature of the Ultimates soon sorts out any minimal runout issues that new rotors might have.