In this tut I'll explain how to make your car in chrome.

As example this CL:

Select the parts of the car you want to chrome:

go to layer-> duplicate layer:

Click in the layer menu at the button "add layermask" see image:

You should get something like this:

Now go to image->adjustments->levels and choose following settings:

Now you can add some brightness/contrast(image->adjustment->brightness/contrast):

And now this is the result (gliming isn't it?):