What could be the problem with my cars wheel?

I have a 1999 Plymouth Neon DOHC 2.0L and i have been having problems with the front end.,. The problem is that sometimes, usually only during braking, The car vibrates pretty bad, and sometimes it makes a scraping noise as well,My brother also told me that he saw my tire wobble as I drove off the other day. At first I thought it was a tie rod, but i checked it and it seemed fine, the ball joints also seem fine, i swapped out the tire and it still proceeds to vibrate and shake mostly during braking. I am thinking it might be warped rotors, but i have no pedal pulsation, the steering wheel does wiggle a little when traveling forward though.... any thoughts?