....is a safety net in case you drive the car past its traction limits.
If you have good car control, and know how to counter steer and such, you can enjoy a non-PSM Porsche with no fear and no loss.
It's there to keep you from oversteering or understeering into the guardrail in a turn, more than anything else.
If you are a good driver, you actually want PSM turned OFF when you are having fun behind the wheel.
If you think you would push the car hard, and push her hard in slick conditions, and you want an electronic safety net in case you "get it all wrong", then go for it.
I drove a 1993 Miata for 23 years without ABS, stability control, or any other driver aids, and it was a blast to power slide through every turn every chance I got. Never needed the nanny.
If you find a good car, and it didn't have PSM, I'd buy her.
It comes down to your comfort level driving hard and your confidence in your ability to maintain control yourself.
