My car's transmission shifts to neutral?

I would advise checking your transmission fluid before you take it to any body. The high g-force could be causing the fluid to move to another part of the transmission where it is not lubricating and doing what its supposed to be doing. Remember that the car has to be on when checking the fluid. If the fluid is full and clean then it sounds like the transmission is going out. Do you know if the current trany is the original or has it been replace before. If its the original it has had a long life and its probably ready to be replaced. If so get ready for around $2,000 repair cost.