Swapping during a series is not possible. I recently did some testing with editing a car during the middle of a series race and found that, when you enter a car into a series, it comes in as is, and changes to the car will not reflect, until after the series is finished, if even then. Hard to explain.....the car you enter in the series is saved data and not the car in your garage any longer until you put it back. I did have some luck in the past writing a joker for tire change, not that I can seem to find it now, lol.