Depends on where you live for the exhaust question, you could run a header through a strait pipe or a custom high flow cat and a smog legal header. Buy a Haynes manual and do the brakes yourself, Midas or Meineke will RAPE you! I know from experience. Valve cover, easy fix, the Main seals will take a little more effort, your "shake" is probably due to the bent wheels or wheel bearings being shot, another easy fix, buy a manual and get in there, it is easier than you may think.
Good Luck,
Norcal