What is the MAP reporting with the engine off? At idle? Did the motorsports guys check you manifold harness? It carries all of the signals from the sensors to the computer. My car had a "map sensor high circuit" CEL and would cut fuel and timing every time I hit wastegate spring pressure, after my first turbo swap. I spent weeks ordering sensors, cleaning grounds and checking for boost/vacuum leaks. Eventually, I got ahold of a use engine harness from another member. After I installed it, the problem disappeared.