Seeing as PSN is down, I thought I'd tackle the final test here as I only had silver. It took about an hour and is difficult because of the fact that ABS is stuck on 1. However, this is how I did it, hope it helps if anyone is having trouble here: Active steering: Strong Sensitivity: 5 Automatic Transmission
Draft the Lowes car from the start past the red car on the left. Entrance speed to first corner should be approximately 223 mph. Be as smooth as you can through turn and exit speed should be around 203mph with a deficit of about 1.5 seconds. Keep tight to the wall and draft up the straight to a speed of 235 mph.
You should be right on the back of the pack now so take an inside line being careful to avoid the other cars. By the end of lap 1 you should be about 0.8 seconds behind the leader and in position 8 or 9. Keep to the left and keep drafting the cars in front. On the next turn you should be able to draft past many of the cars and come out of the bend in position 3 or 4 with a deficit of about 0.3 / 0.4 seconds. Then you can draft the last few cars on the back straight easily and go into the final turn in 1st place.
To win the test, keep your eyes on your mirrors and defend if necessary. I had led several times going into this corner and finished 2nd or 3rd because I was passed on the last straight. Race to the line for that final gold trophy at Jeff Gordon Nascar school!
Yeah at the end when you're defending there is a chance you will get disqualified which is such a pain. Try and stay away from the racing line so it's less likely they can draft you out of the final corner. Also carry as much speed as you can into the final corner while at the same time avoiding the wall. Good luck!