I check out Wim Schermer's blog every now and then. Always an interesting read, particularly with the google translator
Wim's "storm strips" (as Google translates it) are quite interesting. If you do a bit of reading through his blogs, it is interesting to note that the primary driver for this is to help prevent a sudden wind gust from actually tipping a quest over !!! Wim states this is not a risk in a Mango due to the wider front wheel track (76cm Mango v 61cm Quest). Wim's latest blog post outlines some foam lining he put in his hood to protect the head (more than it already does) during a rollover. He quotes several instances of quest rollovers where the hood offered good protection, but he sought to make it even better. Wim and several others on BROL etc have also recently reported damage to their quests after incidents where they were cornering too fast and had to steer out of the corner to avoid rolling, resulting in a collision with bushes, embankments etc.
Quests of course are the market leaders in terms of volume (mangos 2nd) with probably 2.5 quests for every mango in existence, so yes they would be involved in most incidents, but I have only ever read about 1 single rollover incident in a Mango, and that was caused by a mechanical issue, not during cornering or wind. As a mango owner, I know it could happen, but you just don't ever fear it and feel very comfortable taking corners at high speed.
The wheel skirts and footholes covers may be interesting for racing in cool climates but I'm not sure how practical they would be for me. Foothole covers definitely not - I need the airflow as well as the heel clearance for pedalling. Wheel skirts I wonder if they would hit the wheels if you hit a major bump during cornering. I currently run 32mm Kojaks on the front and would never go any wider as it increases your turning circle, but the wheel arches are designed to accommodate slightly bigger tyres, so maybe some small skirts would be ok. I wonder how much benefit they would really give though. When you're not track racing and chasing every 0.1% improvement, I strongly doubt I would notice any difference on my daily commutes