2/2007 Aurion auto, 112000km, under light to medium throttle in 40 to 80km/hr range has a wobble/vibration. Not felt through the steering wheel, felt through the seat. When car is fully loaded more noticeable and when climbing steep gradients very noticable (and felt through the steering wheel). Bleeds out after 80km/r. At 100 km/hr and above smooth as silk. Checked by 2 steering specialist and local Toyota specialist. Engine mounts seem OK, torque converter not locking, all suspension bushes ok, driveshafts and CV not obviuosly damaged or worn. Wheels good, tyres new (occurred before new tyres). It has the typical Aurion drfit to the left. Don't want to chase the problem by replacing parts till we find it. I'd appreciate thoughts on what the cause might be. Thanks DS