Got mine about 6 months ago...and since then my car has been vibrating on hard accelerations. I never though it would be the driveshafts (were brand new...) until my mechanic checked them and told me that the play of the inner bearings was waaaay to much, and likely the vibrations came from there. I am now planning to contact J&R to check if warranty will cover this and to get new ones (2 years warranty).