So, in TM2, there's a wonderful tool called "Shoot HQ" (I think). Anyway, it can be accessed directly through the Mediatracker, no photoshop skills required!
To do this, pick the replay you want and load it up to be edited. Go to the point in time where you want to take your screenshot, and then go to the top-left of the editor window. You should see what look like two little pieces of film, one with the letters AVI on it (for video), and BMP. The BMP, of course, is to shoot pictures. Before you click that, make sure you have the camera angle set to where you want to take your shot, of course. And, if you want motion blur, at least in my experience, whatever mediatracking you have set previously, you need to change it so that the camera is "anchored" on the car. When I forgot to do that, the motion blur effect blurred -everything-, not just the wheels.
So I got a muddy mess. Anyway go in to shoot your shot, turn all options on up to max to make everything pretty
and then shoot your video. Good values I've found for making wheelspin look good without over-blurring? Set motion blur in your options (in the game itself) to .25, and set the screenshot duration to .005. However, if anybody has a better suggestion, I do welcome it as I'm new to this whole mediatracking and screenshot scene. I hope, though, that these tips can at least get you started 
