I am in STL too, one advice would be to go to Reid Vann and speak with JOhn. Reid Vann (if you are not familiar with it) is a small shop across from Parktown, much more friendly than Plaza or Parktown (where I don't like to go as it is way too big and you feel like an number)
John is very honest, patient and experienced and would be able to give you good advice as he knows Porsches very well.
Good luck!
http://reidvann.com/