Steering wander, adjusting EPS assist

[Snubba]

Hi folks, you might remember me from such threads as "Is steering wander caused by caster?"

I have been disappointed with my Liftback cruising because it gives a disconnected feel when cruising at 65mph. It wanders down the road and needs constant steering correction to keep it straight. This is different from other cars where you can just sit there with one hand the wheel while resting it on your leg and correct the steering with less mental effort. Driving the Yaris long distance takes more mental energy to drive than other cars.

So I recently found this link by etimago (thanks!):
http://www.autospeed.com.au/A_111532/cms/article.html

So I did the same basic principle as the article and placed resistors in line of one of the steering torque sensor's wires (TRQ2, the yellow one, it comes right out of the bottom of the EPS assembly). If I installed too much resistance, the EPS would fail just the like article said. So I found a good number that wouldn't shut off the EPS when I jerked the wheel from side to side while parked on asphalt. It was 267 Ohms. I used one 220 Ohm and another 47 Ohm resistor in series to add up to 267. I THINK it made the steering effort decrease but whenever I think something made a difference, its safe to call the experiment inconclusive (because I tend to see "improvements" when none were there). An interesting thing, when I used 470 Ohms, it wouldn't fail until I jerked the wheel from left to right when parked on asphalt.

So the article mentions a "torsion bar" in the system. It is used by the steering torque sensor. So I took a big crescent wrench and put it on the steering shaft at the universal joint next to the firewall and held the shaft in place. I then turned the wheel and found SPRINGYNESS! It would move about 1/4" at the seam between the column cover and steering wheel cover before it stopped like it hit a block.

So I think this is part of the problem or maybe the whole problem. Maybe its this torsion bar and castor combined. The thing is that hydraulic power steering systems use a torsion bar too yet they feel fine.

What say ye?
Does anybody have experience with a direct-drive steering shaft in the Yaris?