^ This, its a GM, itll never have everything right at the same time.
Careful with valve cover gaskets the OEM ones started fires on some of these cars, if it hasn't been replaced yet, a GM dealer will replace one of them no charge.
Flush the transmission, spark plugs, check the cooling system make sure its not all goopy from mixing fluids or Dexron decay.
if you have to do anything like replacing ball joints or hub bearings, go ahead and replace the sway bar end links, new ones firm up the car a little in my experience. They only cost like $10-$20
