Questions about Cornell University Summer College (CUSC)

I am a Junior and have applied and is admitted to attend CUSC this coming summer on the 3 week course Digital World and You (my schedule does not allow a 6 week sadly). However I am still choosing where to go for the summer, so would like to ask some questions

  1. How much does this help my chances of admission into Cornell ED or other universities? (Cornell is my dream school though) *I do have the 'prerequisites' to have a chance at being admitted though, e.g. 1560 CR+M and various leadership positions, and currently have 39/42 for IB courses (expecting an increase) ;)
  2. How tough is the program? How hard is it to get an A or B? How is the grade determined, by a percentage or depending on how the rest of class did (percentiles)? Will getting a lower grade destroy my chances?
  3. In terms of general ability, how is the student body in these programs? Will there be a lot of competition?
  4. What is the general experience?