sasquatchman
Here's a good site I found that had some Photoshop tutorials.
If anyone has any tips on how to get the light glow to overlap I'd be thankful (my airbrushing sucks).
Pretty good site ... I found it quite useful rather than exploring the tools myself
For light glow, I would try to use Magic wand to select the light glow that outside the car, then use the selection and create a layer mask on the layer with the light glow. Inside the layer mask, black will hide the stuff on the layer, white will show the stuff on the layer. So if the light glow appears too much, put the grey darker. If the light glow doesn't show enough, put the grey lighter.
I usually editing the layer mask under the channel tab, turn on or off to the RGB or layer mask when I comparing and drawing mask
I had experience with dirt and smoke editing, but not the light glow
but I believe they are pretty similar
if you haven't tried layer mask before, should try it now
Its just very useful for multiple car editing, specially when the backgrounds are slightly different between layers
edit> Camaroboy.... pretty good for a start
your 3 hours are well spent