And now that the Thresher actually has some advantages over the Magrider (before the only thing the thresher had over the mag was slightly better accel and the ability to go into narrower places) it's actually worth the 3 points
That thing was made outta eggshells before
As for the physics engine, I haven't noticed anything. Then again, I usually am on my basilisk, which ramps on hitting pebbles.