I've had a pano roof RS wagon for 2 and a bit weeks now and you're right ... the pano glass has a very heavy tint with good heat protection. I ordered the pano roof mainly to lighten up the all black/grey interior and thought that I would always have to close the electric blind when driving in full sun in warmer months. Much to my surprise, I only close the blind when parked outside on a hot day but the sunroof blind open button is always pressed just after the start button (and today was a 31 degree sunny day). My family really love it too... especially the back seat passengers (there's a couple of pics of the roof on this thread on page 227)
I highly recommend it ... it's one of my favourite features of the car!
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