1. For a 88 lx 5.0 how big a difference is a new rack a pinion and control arms? Is it necessary?
  2. depends on your goals for the car
    I assume you mean the front control arms (A-arms)?
    if it's stock and there is no issue with them, leave it alone

    If you mean rear control arms, there are many benefits to aftermarket arms. Searching will find your answer. :nice: