Im sure u got the same problem as i have, its very random. i found it did it when u let your foot off the throttle for a corner or roundabout and when u get back on it starts to shake realy violently but as soon as u back off the throtle and get back on it totally disapears? im thinking attessa because ive had mine i rwd (front shaft removed) since the dyno tune and it feels alot smoother now. its not sumthn thats out of balance because it doesnt get better or worse with speed im thinkn transfer case or sumthn. or its just slack in the gtr drivline they are overbuilt.