Sorry about your problem man. All I can say is that when I installed my new Powerslot Rotors, I felt an immidiate difference. I too had the same symptoms that you had. Once I replaced the stock rotors with the new ones though, the problem dissapeared on the first drive. I really don't know what to tell you except call the company and find out about a replacement. Also, if they do give you a replacement I suggest that you do the install yourself. That way you know the install was done to the letter. Its really an easy job if you have basic hand tools. I don't remember the right size for the axle nut though sorry (I think it was a 36mm but I'm not quite sure).
On another note, if I were you I would do alot of the upgrades myself. You get a better appreciation of the outcome and you learn more about your truck. I am not a seasoned mechanic at all. But with the proper instructions and This Great Website you can work on almost any part of your truck yourself with the help of a friend (or in my case, the wife
). I wish you luck on your replacement.
John