I've messed with my setup a bit, nothing too fancy just lower tyre pressures, more rear wing, and put the rear camber on -1.70. I was running 2:03.0 on default setup, and now I'm down to 2:02.0. I have no clue how on Earth people are getting 1:58, that seems impossible for me. Setup seems to go a long way with these cars though. Wish I could get my hands on their setups, I know absolutely nothing about setting up the suspension side of things. Probably a lot of time to be gained there.
It would be good if the comp was locked to a setup somehow, so everybody is on equal grounds and it's all the driver, not whoever's car setup is the best. It's Worlds Fastest Gamer, not Worlds Fastest Car Setup.