OK, Its only been a week since the VGs were installed on my Volvo wagon. Its still too early to tell, but my FE has pretty much remained the same...then again, my time on the open highway has also been limited.
It was raining and foggy this morning and I did notice something kind of unusual in the water mist behind the car while driving on the highway during my commute...two
slightly visible, counter-rotating vortices extending from the roof area. My rear lip spoiler is still on, but the vortices still seemed to flow level with the roof height without being deflected upwards. The spoiler will be coming off in a few weeks, so we'll see it some downward flow can be induced. The next time it rains, I plan on letting my Wife drive while I sit in the back to observe them more closely.
On another note, my co-worker has noticed a cleaner rear window on his A6 Avant. But he did tell me that it gets just as dirty @ lower speeds.
Also, my Dad's VGs came back from the bodyshop this week. They were painted Mazda 'Silver Green' and the bodyshop did a fantastic job in matching the color. Total cost for painting 10 VG fins...two pepperoni pizzas(it helps having friends in the autobody biz
) They'll be installed soon.