If I understand you correctly you rotoed a shot, then stabilized the shot with Warp Stabilizer, and now you want to apply the stabilization to the rotoed shot.
Your workflow was out of order. Remove the stabilization from the shot, pre-compose the roto and the background shot, then stabilize the pre-comp.
If that's not what you are doing look at this:
That looks great, im not sure if that is exactly what im trying to do. Here is what I have Layer 1 - the roto video of the car with no background (looks great but i'd like to remove the camera shacking) and Layer 2 - the regular video of the car that i ran stabilize motion on a mail box so the road and everything is not jumpy but thar car can still move across the road.
Both layers do exactly what I want but i can't get them to combine.
Also, how do i "pre-compose" a layer?
Thanks for all your help.
It's very simple to solve your problem. Remove the stabilization from your footage. Put the rotoed copy on the top. Select both layers and then go to Composition>Pre-compose or just grab your original comp and drag it into the new comp icon in the Project panel. Now apply stabilize to the Pre-comp and you're done.
You should seriously think about going through the getting started materials.
Thanks for all your help. It's been 6 years since I used AE, so it's all very new again. The video help was great though. I forgot that the layers were just that, like in photoshop.
Thanks again for all the help.