1. Make a pit stop before your tires get red.(after all by the time those tires go out, you are so far ahead, that you can spare the 40 seconds...)
2. No downforce, no camber, no toe, and experiment with shocks and springs.
3. The difference between formula one and indy is the rules that regulate their design. Formula one is controlled by the sanctioning body "FAI" ("federation automobile international" the real F.A.I. is in french, but basically thats what it is...)
For every series, from the local drag strip 'run what ya brung' to the Formula one, there is a group who sets down the rules. K.A.R.T. and INDY have had a falling out, and last I heard there were 2 sets of rules. The Toyota Atlantic cars look much like Indy, and those of you from the U.K. are likely familiar with the ford formula 3000.
in summary the difference between indy and f1 is the rules limiting the design of the cars. Typically the f1 will cost more, accelerate faster, and turn better. But, you cant see f1 on ABC on saturday...