Smooth collision, disable collision

So, i'm making 2d top-down racing game, i have car, wall, tires(drift trail)

I would like to make collision between car and wall smooth.

And i would like to add the trails only when drifting(can live without it)

Check the game and u will understand my problem.

Here's the link to .capx

You're using a 'step' behaviour plugin which means anyone without that plugin can't open your .capx

Just letting you know.

Can you fix it?