Jupin Racing

There are two up-pipe models existing for the new age impreza, and i would like to know which one to fix : the one with the hole for the sensor (by the way what's the use : pollution, temperature ?) or the model without any ? In that case, what's becoming the wire ? We throw it away ? Please help me, that's a clue i can't solve on my own this sunday, with every shops closed

Greetings from France.