Strange indeed.
From what you describe I assume this must occur when you change gear???
(as if you lifted of normally and didnt dip the clutch the engine would continue to run anyway being driven by the wheels if you like and so would not drop below idle).
So, thinking through whats happening when it occurs(if my assumption is correct above), and also that you have changed *nothing* else.
TPS is telling the ECU there is zero/minimal throttle, this is normal.
I'm not familiar with the kit but I assume it exploits some ram air advantage, the ECU *may* now be receiving a signal telling it that there is significant cool intake airflow but this is in conflict with the TPS requesting minimal throttle. The ECU might be cuting the injectors as a result but I'd be surprised if it did this to the extent that the engine cut out as the lambda sensor would then start to indicate it had drifted from stoichiometric ratios.
When you say the engine cuts, what exactly happens??? Do you slot into another gear hit the throttle and it picks up again?? Or is it misfiring?
is it consistent? does it happen all the time? at all temperatures (engine and ambient). Is there any time it does not happen?