Ok - just ran a test where I ripped RideQuality out of the trackrule. Most interesting. As I had played around manually setting the RQ value in the afore mentioned curve, the value (80) remained tied to the track, the rest of the route defaulted to 0.
With a RQ of 0 there was barely any lurch noticed entering a curve - certainly no more than I'd expect on a real line. The biggest thing I saw was that gradient points are going to be a huge issue now - going from straight track to a .3% grade introduced a major lurch to the ride even at 0 RQ.
and yes, that section that was set at 80 ... ride 'em cowboy!!

I think the lurch might be noticeable headed into an SE curve because RSC coded SE to raise the outer track and dip the inner track, whereas in real track to my knowledge, only the inner track is dipped (corrections welcome if I'm wrong on this point)
I'm also still thinking that RQ is tied somehow to the inertia value of the in-cab-camera
@Jerry - the biggest challenge before us route builders with SE is that RSC coded it to be tied to the tightness of the curve rather than to linespeed. As you say, things look pretty nice in the HSC - along the Curve itself the radius is what 300M? Porting the same values into a route with much wider curves (there is one curve on my route not in a yard that is tighter than 3degrees) the cant is much less noticeable to the eye, but the way that cabsway is coded you definitely know about it!
-barnez