Shootout: Vicki drives two Audi TTs — one with a manual gearbox, one with the semi-automatic double-clutch S-Tronic system — to see which is quickest around a track.Fifth Gear puts fuel additives to the test to scientifically see if they really do improve engine performance or not.Tom Ford drives the brand new Fiat 500 Tiff takes the £225,000, 224 MPH Gumpert Apollo out on the track.Jason goes offroading in the latest Bowler beast, the Nemesis.Jonny meets up once again with the owner of the world’s fastest street legal car, a Vauxhall Victor named “Red Victor 1″, to see if they can break the quarter mile record.