After putting M3 mirrors on my friends 206 gti, we knew that this would render the display for TEMP outside useless.
Little did we know, but this is a refernce point for the A/C in the car and the air-con dosn't function without ( just blows hot air) this external sensor.
Bought at $180 bucks it was money badly spent, but they did look trick, just think about this before/after mirror alterations.
Cheers xqisid.