With the cl9 it is also wise to check the grounding wire near the battery. When this is corroded, electrical current doesn't flow well and create burden on system like the starter motor or alternator. Good to check the battery as well as winter is approaching.
Another option is a reconditioned or remanufactured unit. You can have a look at Amazon.

Unfortunately (or fortunately) there is no right or wrong answer with this, everyone will have different opinion based on previous experience and budget. You would think new OEM starter will be the best but it will come at a cost. If budget is less of an issue, I would not go second hand from the wreckers as installation cost or labour is not cheap. But this also depends how long you are planning to keep the car.