25 to mph is a personal limit that I set. I am not a young spring chicken any more these days with my reaction times or eyesight. I like and enjoy uneventful drives to where I am going camping. I like taking my time. I like high MPG while towing. I'm Dutch, and I am almost as cheap as a Scotsman.
Just my belief that by driving slower and obeying the speed limit (oh and BTW, for all of you out of staters that visit here in CA, some folks need to read the speed limit road signs on Interstates, the speed limit is 55 for all trucks, including SUV's, with trailers, on Interstates, including I-10), it increases my reaction time.
While my Touareg is capable of such maneuvers, cones belong on a track or a race course, and are a poor substitution for the reality of trailering in a state like California, with 40 million people in the state, many of which don't read English, or perhaps don't belong here, or perhaps are stuck with double digit IQ's on our public roads, in uninsured vehicles with no drivers license. Trailering, so far, in the west, in any other state, is a cake walk, compared to trailering anywhere through Southern California's Metropolis mess. Sad that I live here, weather is great, the people, not so much anymore.
As to the sway, it is inconsistent, and in my mileage, seems to be a combination of factors, all at once. Big Buses, going very fast 80 to 85 mph, think Van Hool, with huge frontal areas and a big bow wave, in Utah, where the speed limit is 80 and folks do 10 to 15 over that, on a whim, with cross winds out of the NW, with the driver straying closer to the right of their lane, seem to be the worst. Big rig trucks that are sleepovers with sloped noses are a non issue.
I can tell you, professional big rig drivers are much better about staying left in their lane when passing travel trailers, part time motor home drivers seem to be clueless as to the affect of the bow of their wind waves on travel trailers, doubt they were schooled on driving them, or they are not very observant.
I have driven both with and without the WDH, if my front end didn't come up 1" and rear end sag 1 3/4", I'd do without the WDH, the Touareg drives for some reason, much better without it, the trailer is free to react to the cross winds without being all tightened up and pushing the front end into the Bots Dots.
The Touareg, from what I have been told, has all the fancy anti sway software, brain power, brakes, and X,Y,Z yaw sensors built in to it... it comes off the same production line as the Cayenne and Audi Q7... it's just shorted on all the deluxe bells and whistle features on the interior, in the Sport model. For $40,000 for a diesel, at year end sale prices, it was hard to say no.
Basically, I really just don't enjoy driving in stiff cross winds. I get conservative, and get off the road then, I've seen too many blown over big rigs, 5th wheels, TT's and motorhomes on highway 395 in Eastern California on my way from L.A. to Mammoth Mtn or Bridgeport... way, way, way too many.
As always... YMMV.... these are my observations.
PS, the aerodynamics of a box, and an AirStream, is not a fair comparison... the Airstream is 4x to 6x the price or more of what I paid for my Palomino. The cD of an Airstream is much lower, and has much less flat surface for a bow wave to have an effect. When I bought the 21 footer, for $13,000, brand new, near MI, I got what I paid for, I don't have the right to expect much more from it when towing. If it ever got broken in to, or stolen, I wouldn't worry too much about insurance or the loss. An Airstream is another story... for that kind of money, I'd be looking into a 5th wheel instead.
