To identify the cause of the shaking while driving, you need to inspect every part of the steering and also consider the tension/compression rods, and also wheel/tire imbalance, or bent wheels..
The shaking while braking is symtomatic of warped rotors.. very common
Above is a good diagram from the FSM. Consider the tie rod ends, the rack bushings, and also any damage/play within the rack itself. If you have the stock Tension rods those are likely very bad.
Battle Version's newest Tension rodhttp://
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Kazama / Tein inner and outer tie rodshttp://store1.yimg.com/I/phase...65465
NISMO rack & pinion bushingshttp://
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Phase2 is top notch!