I have see quite a few posts on wind deflectors, so thought I would my thoughts.
I have now had 3 different types so maybe can help others with a choice. The ones I have used (in the order I used them), with pros and cons are:
1. VW OEM:
These stick on the outside onto the painted surface of the door around the window. (cant comment on fitting as they were on the van when I got it)
Pros: Pretty quiet
Cons: Not the most attractive, eventually they started to come away and were very difficult to remove and left a slight 'shadow' in the paint, most expensive of the 3.
2. Team Heko:
These tuck onto the channel where the window glass goes.
Pros: Look great, ok to fit but the clips can be fiddly, cheapest of the 3.
Cons: Fitting needs double sided sticky stuff and metal clips but this has caused some people to have issues with the windows re opening when they get to the top. Worst con for me was because of the metal clips preventing the window sealing fully there was always a slight whistling wind noise especially when get above 50mph.
3. ClimAir:
These also fit in the window glass channel. However the differences are they dont use the sticky tape or metal clips, but a small bracket on the end near the mirrors.
Pros: Look great, easy to fit, the most difficult being drilling a small 1mm hole in the black plastic trim, I believe them to be the quietest of the 3 (close with OEM) no whistling noise like the Heko.
Cons: Having to drill a tiny hole on the plastic mirror trim.
Overall in my opinion the ClimAir are the best as the advantages over the others outweigh drilling the tiny hole for the bracket.
HTH