steering issues, what could it be??

[B99Brighton]

OK heres the back ground on my soob issues. When lived in colorado this winter i had a slight run in with a curb at a 10- 15 mph. It did some pretty extensive damage to the left front suspension. It bent the lower control arm and it had to be replaced. While I did this I figured that i should also address some other issues with the car. I replaced the left lower control arm, the wheel bearings, ball joints and replaced the brakes with new calipers, ceramic pads, and drilled and slotted rotors from Napa. Ever since then have had some steering issues. I can feel a heavy vibration at highway speeds. 50-80 mph. the car also seems to float side to side when driving in a straight line. It will then pull to one side or the other upon braking. This also happens intermitantly when cruisin down the road. After taking it to an alignment shop they determined that the rack and pinon was also damaged in the accident. I believed, and the shop too, that the valve that returns the wheel to center was damaged and this was why the car would not feel solid in straight line driving and also pulled easily. The outer tie rods where also badly worn, could move them by hand. So recently i have replaced the entire rack and pinion with a complete assembly from the dealership. It also included the inner and outer tie rods. i then had it aligned by the dealership in Moblie, AL (my new home). The rack was a little expensive:banghead: . After about two weeks of driving and thinking the problem was corrected the symtoms returned. I am perplexed!? I'm not sure what could be causing the vibration and pulling conditions. It feels worse than unbalanced wheels and nearly every part of the front suspension is brand new with quality parts. The struts pass the bounce test and the upper strut mounts look and feel ok, no cracking in the rubber, etc. They are also noise free, no bumps or cluncking. Any ideas from the usmb that could lead me in the right direction? I know that something could be wrong in the rear suspension, wheel bearings or brakes so I plan to check that out when I replace the master cylinder and add a brake support bracket here in the near future. I will disassemble the rear and visually inspect it all. I will hopefully eliminate the rear as it definatly feels like the front because all of the symptoms can be felt through the steering wheel. Any ideas?? I'm just about out of them. thanks to all.