shaking elantra

05 elantra GT 180000 mi. shakes at highway speeds. new tires & alignment, new struts, new brakes, new tie rods, new control arms w/balljoints, new wheel bearings, rims checked..... WHY still shaking???? im stumped. any ideas??

Just because you have new tires and wheels, doesn't mean they couldn't be out of round.

Try this:

1) Determine if the vibration is in the steering wheel or in the seat.

2) Rotate tires front to rear.

3) Did the vibration move? If it did, then it's the tires and wheels. If it didn't it is something else.