^If you read the reviews for the MPSC's, it seems those tires are even more sensitive to proper temps.
"Folks, do not use these tires for AUTOCROSS. Period! They do have to be warmed up and you just cant do this at most events*. I changed from PS2 to Cups and I was like the car was on ice."

*This is because at an autocross event, you spend most of the time sitting in the car, waiting your turn, or pushing it up to the start line. You get 1, maybe 2, sighting laps before your timed run. The MPSC's are still cold. Meanwhile, the Kumhos are popular and highly rated among autocrossers.
"The v710 is amazing for autocross. It warms fast, stays predictable throughout, corners in like on rails."

I think maybe the MPSC's could be part of your traction problem. Unless you are really on them constantly, they might not be any better than regular tires.