Stock.

Depends on your power goals. People use different turbos depending the way they want their cars to feel so. I would ask a more specific question:
How much power are you hoping to make?

Pon cams are what I would go with.

but I made 310ft lbs of torque on a Tiny 28R and it feels like a rocketship lowend but drops off top end.
When sliding the torque is instantaneous