Steering problem
2001 Ford Mustang 6 cyl Two Wheel Drive Automatic 145000 miles

The mileage is all highway driving, new outer tie rods.
wheel and tires are from a Mustang GT.
When driving down the road, if i go over uneven pavement, the car will turn a little to the side that the uneven pavement was on. the worst it is, the more the steering will turn. I can even fill the white line in the middle of the road whan one tire go over them. at high way speeds it fine. It at lower speed on city streets. Had front end aline 2 times in the past 10 mouths. Also has new front shocks.

Ok first off how wide are the tires? For a car to follow the rut of a road is normal. I have done many alignments myself and you can no compensate for uneven roads. So to a point this is normal.
Now just for piece of mind check the lower control arm bushings and the rear control arm bushings. If they are loose then this can add to it

The size of the tires are 245/45 R17 95H
I had this size of tire on the car for the last 90,000 miles or so. It has been doing this for about the last year (getting worst as time goes on). I do about 23k mile a year.

Ok with that tire size the width is more apt to follow the curve of the highway. Now with that said have you checked the bushing and the ball joints? How do you drive the car? Now if any are bad replace them. If the bushing are bad get urathane bushings like for energy suspension. The other things you can do to tighten up the front end is to put in a strut tower brace they help alot ( I have a 98 Mustang and I drive it). Let me know what you find and we will go from there.