Enter the following as Passwords:
WLLVDDAll codes enabled GGWWOOAll cars & cups NRNNRRCheetah car TRTTLLCobra car PXPRTSMaster mode and bonus cars YMSTTRPanther car SDSSRTScorpion car LGSSSXCrystal cup CRKKYYDiamond cup DZPKKKZenith cup
On Canyon just after the start go to the far right, there should be a gap in the wall go through it. It should get you first place. At the first corner go to the far left there is a road leading down, follow it and it should bring you out in front by heaps. On Island just after the 180degree turn go into the first opening it is a lot quicker than the other 3.
Thanks to Revolution readers Nick Barker, James and Mister Mistereeus!