Not much any of can do other than tell you to have the front end of your car inspected.

How many miles are on the car? If getting up over 100K miles, there is the possibility that some of your front end bushings are worn and there is play in them. Common failure items are compression rod bushings and translink (lower control arm) bushings. They break and tear and as a result the front end will float.

You need to get under the car, put the front end on jackstands, take a big prybar and start pulling and pushing on the various bushings to see where the movement is.

You can also take a peek at your tires and see if there is any abnormal wear forming.

Outer Tie rods - Adjustable steering component that is used when car is aligned. They fail due to a torn rubber boot.

Inner tie rod - Attaches to your rack and pinion and the outer tie rod attaches to this. If you disconnect your outer tie rod you should not have a lot of play moving it around. You can also jack your car up and try moving the tire in side to side, up and down, and if you have a lot of play or hear noises odds are they're bad.

Compression rod - large arm from the subframe of the car to the steering knuckle. Suspension component the rubber bushings can go bad on these.

Lower control arm - Piece of metal with bushings that runs from the knuckle to middle of subframe. Your shock and sway bar links are attached to it as well. If the bushings go bad on these it can cause issues. They also can become warped and grind the metal down where the bushing goes into (happened to me).

Bushings - Just a piece of rubber, polyurethane, etc.. that protects metal on metal contact.

Upper control arms - Looks like a large U where the top of the knuckle connects to.

Get an alignment, tire balance, and if you have aftermarket wheels make sure you have hubcentric rings installed. If you don't have those you can get A LOT of vibrations from your car.

Make sure your rims aren't bent either.

My inner and outer tie rods were worn. They had excessive play in the inner rods. The outer tie rod ball joints had alot of play too but no torn boot. You can't go by the condition of the boot. The best thing you can do is unbolt the outer tie rod and move the ball joint on it by hand to feel for unwanted play and or clunking movements. Even if the boot doesnt rip, the grease inside breaks down after a while and causes the balljoint to wear.

Also my inner and outer tie rods didn't cause any shaking on the highway like the OP mentioned. More like loose sloppy steering and uneven tire wear.

Compression rods were the culprit to the annyoing shaking. Felt like I was driving on bent rims.

Btw go with aftermarket parts. Much better than the crappy oem stuff. I've found oem suspension parts for these cars to be total junk. If you go aftermarket stick with Moog. My inner and outer tie rods I replaced with Moog which have servicable balljoints that allows you to regrease them with a grease gun whenever you want to preserve the life of the balljoint. Grease that breaks down is what leads to the balljoints failing in the first place.

That's your opinion. Mine have lasted me 120k just fine and I plan to put them back in when necessary.

wanna hear my opinion of your opinion?

If your opinion if different than my opinion, then I am offended and want it banned

Surprised no one mentioned bad shocks, at that mileage they can cause big problems If they're worn out.

Man im confused. I got brand new tires and alignment so those possibilitys are out of the picture but i will jack up my car and see if anything is loose or in bad condition.

Results pending

Are your tires on the stock rims? If you don't have hub centric spacers it can cause all kinds of vibrations.

Hard to advice these kind of things.
People run in here asking question about the problems they are having with no description of the car, maintenance done to it or parts history.

Compression rod bushings and shocks would be first things I'd check. Everything else that can cause vibration will cause it at much lower speed.