Problems with the fueling, the engine was pulling 9.8 on timing correction which was generating a fault code for "engine torque limit exceeded" I had the car remapped again which stopped this. I then had the common
problem with the exhaust sensor seeing too much gas and generating code P0420.
For all i know it could be an incompatibility issue between my original map and the pipe, or it could have just been down to the exhaust sensor position all along. I honestly don't know.
Either way, the piper product is excellent. The change it has made to the engine and responsiveness is amazing and worth the hassle i went through.