I went to several shops that had pieces laying around, and of course one of my friends own shop had some. It's thin aluminum, not thick at all. So I just brought them home and cut them to fit. Didn't like the plastic Spectre pieces I originally had. One piece was actually melting! I have yet tried it at the track to see if there is any difference. I guess I'll find out next month and compare the times to Thumper's car.