stuttering physics

It's hard to know precisely where your problem is when you don't post any code, but often, physics stuttering has to do with incorrect usage of time dependent physics, eg. using physics in Update where it should be FixedUpdate, or using it in FixedUpdate but still multiplying by Time.deltaTime, and so on.

Anyway, post some code, then I'm sure someone will have a look at it.

Try setting Rigidbody->Interpolate to Interpolate

http://docs.unity3d.com/Documentation/ScriptReference/Rigidbody-interpolation.html