Hi J,
That shot of Dave's 172 was using two 500W flashes. You can see where abouts they were placed due to the light on the ground. As Nick said, you can use a second exposure for the background, but I didnt do that for this shot as I was happy with the background lighting with just the two flashes.
The photos in my thread Nick posted too is much simpler. No fancy lights or anything, just a 'torch' effectively and a long exposure. Just make sure it's a LED torch, as they give out a nice white light.
You wouldnt be able to get this effect in photoshop as it's the flashes giving the car the light. If you only had one flash though, you could light the sides of the car separately and then merge them in photoshop, but thats a lot of work! Kind of what I did in the M3 shoot in the link.
Hope that helps a bit, and other questions feel free to ask