DTM door mirrors

[rainagain]

Has anyone had any gains from swapping their OEM mirrors for DTM style mirrors? (DTM mirrors get their name from the Deutsche Tourenwagen Masters (DTM, German Touring Car Masters) which is a touring car racing series based in Germany, the competitors designed them to reduce drag!)

My mirrors on my Peugeot 206 currently look like this:

http://www.aoeperformance.co.uk/ekmp...rim-2305-p.jpg

I was thinking of changing them for these:

Black DTM Style Wing Mirrors

But I'm worried if the new mirrors will cause problems with the airflow further back, any ideas?