No. I don't own one. I know guys who have done well under my best, all legal no cheating ect.
47.500 was the best for a while with the escudo, think thats been beaten now though.
There is a little trick within the game, which seems to work best at Red Rock. some call it ground effect.
You put springs to minimum, dampers to max, you can then go much faster round corners, the car gets sucked down onto the track, giving you greater speed round corners.
When you've got as much experience on Gran Turismo as me, you get to know these things, I've been playing the game for years, nearly every day, with some real good guys on many different websites.
Gameshark is not something we aggree with, why bother cheating, it does not make you a better driver.
cya