I just replaced the starter on my 3.2. I eliminated all other possibilities before pulling the starter but the final symptom was that the voltage everywhere on the car was a strong 13.5 until turning the ignition to START - with no cranking at all, the voltage instantly dropped to 7 or 8 and kept dropping until the ignition was released.
After pulling the starter, it sounded like there was gravel and sand rolling around inside it. I put in one of the lightweight hi-torque starters and (after a few modifications to the ignition wire AND starter cable
) it fired right up. stronger than ever.