Is highway wander caused by caster?

[Snubba]

Hi folks, long time member, long time lurker, newbie poster.
At highway speeds my 5 door liftback needs constant attention to drive in a straight line down the road. I think I found out why. I came across a forum discussing the new Toyota Corolla's similar complaint with the steering. A coincidence is that the Corolla has electric steering assist too. Check out posts #94 and then #98.
http://townhall.edmunds.com/direct/view/.f1d0fdf/90
Post 94 is an account of a guy that had his caster adjusted and said his steering improved (less wander). Then in post 98 this other guy replies that he always thought the reason Toyota gave it less caster is that it makes steering easier. Easy steering would require a less powerful and smaller electric motor, smaller wires, smaller alternator, battery, etc. He thinks their motive is to save money on the smaller parts and I agree.

In the forum I linked to, it seems a lot of people don't understand what the complainers are talking about. They reply saying the electric assist is great. Which it is. I love mine in parking lots. And I love its simplicity because there is no hydraulic pump sapping power and potentially getting leaks in the future (however I'd rather have no power steering altogether because I don't think it is needed on such a small car). Back to the topic, the the issue is the wandering, so naturally the complainers blame the electric assist because it is the new technology associated with the steering. The theory is that it is not the electric assist that is the direct problem, but the caster setting. If this theory is true, the electric assist is the reason for the problem, but indirectly, because Toyota set the caster to make steering effort easy on their new electric assist steering technology and this setting makes a the car wander. If a car has electric or hydraulic power steering, it shouldn't wander down the road as it goes in a straight line. I've driven 8 cars may miles in my life ranging from an '84 Corolla to a '64 Dodge Dart to a '90 CRX to a '95 BMW 525i. They ranged from light weight and no power steering to moderate size and advanced power steering. They all did not wander as bad as my Yar-Yar.

It appears many Carolla owners are speaking up about the issue. Check out post 101. It has this link to an article where the NHTSA is studying the Corolla problem.
http://content.usatoday.com/communit...ing-problems/1
Why is the same action not taken with the Yaris? Until now, I attributed the wander to the small size, light weight, and tall height making it easily affected by the wind so I didn't complain to anybody but myself. I think other people haven't complained because they attributed it to the same characteristics as I just stated.

FYI: Here's a link to the NHTSA (National Highway Traffic Safety Administration) where complaints can be made.
http://www-odi.nhtsa.dot.gov/ivoq/index.cfm
I hate to put extra stress on the beloved mother of my Yar in this time of other recalls, but what the hell Toyota?! I expect a straight tracking car! If anything, make a car with no power steering. There are other Americans like me that don't require unnecessary fluff (power steering on a small car) to powder my butt with.

I am a tweaker (with mechanics, not meth ), and now I want to have my caster measured and depending on its angle, have it set to the more extreme angle while still being within spec. In order do this it looks like my option is to cut out the cone shaped protrusion from the strut tower that the top of the shock fits into and then adapt some other vehicle's camber/caster kit to the strut tower and shock. Is anybody out there that has changed the caster? Any recommendations on a good shop that knows what they're doing in So. CA? Are there any camber / caster kits for the Yaris in this country or others?