frontend problems!!!!!!!!!!!!!

I have a 94' cutlass supreme with a 3.1L engine. I just bought this car about 6 months ago and the frontend shakes when you press the brake pedal. this what i have changed already done to this car: changed the front strut cartridges, replaced brakepads, rotors, bled the brake system from front to back, four new tires, wheel alignment, replaced front wheelbearings, and prayed alot. you feel it more when the car is braking from a higher rate of speed(+45 mph). car drivers great otherwise. any info is appreciated!

Check the runout and parallism of your front and rear rotors.
Most vibrations during brake apply are caused by warped rotors.
Also use a torque wrench to tighten your lug nuts....rotor warpage can be caused by improperly torqued lug nuts.