Nope!
I never race, I only use "free practice", trying to get better and to find the right setup. I also do this in GT4 ==> free run that is. I am not and never will be interested in competing myself with others. I only like to improve myself.
I've won loads of races, I started off using 90% difficult AI but I found that to be too easy, I use 110% now, any higher and I CAN win but I find at the moment 110% gets the blood rushing and a small mistake won't ruin my chances in a 2 hour race.