Just had a quick go with the new beta. Still not quite sure what to make of it. Seems like an improvement physically over 1.03, and the sound is definately much better than before.
Several issues though; the tyre squeal is very nice, and pretty convincing, but way over the top. You only have to push the car to within 50% of the limit before the tyres start screaming at you. From my experience you have to push a tyre pretty damn hard before it starts making so much noise. It would be nice to have a subtle scrubbing noise when you aren't pushing too hard. I'm also pretty certain that the front tyres aren't producing any tyre squeal whatsoever either. If you induce lots of full lock understeer, no noise, and even if you lock the fronts up, no noise..
The rumble strips are also extremely loud, and I'm getting no external engine sound when the car is not within a few metres of the camera.
Finally, why is it that LFS is the only sim which doesn't require 100+ fps to get managably low steering lag? I tried applying lots of AA, and my fps dropped to 80, but the steering lag was seriously poor at that framerate. I found it needed to be over 140 fps before there was no noticable input lag.
P.S. This is only what I've noticed with the F1600, as I only have the demo.