IO540
As 2D said. I know nothing about autopilot misbehaviour in TBMs and don't plan to speculate about it. My knowledge of autopilots ends with the one I use - in an Arrow III - which must be OFF below 1,000 feet. I know why it must be off, and I comply with that ruling.
I understand (from some people I respect highly) that TBMs can bite when low, that this involves left-wing-down, and that engine torque may be involved. I don't fly a TBM, and have no intention of getting into one until I've read the AAIB report on these accidents.