You are ment to do 100 miles before stiffening them up to run them in but as you said it is very bouncy to start with so drive carefull. With the rear as has been said when you lower the spring ten mm lower the shock the same, and the spring preload the locking collars should just hold the spring so it doesn't move but you can lower the spring if you don't like how bouncy it is, however I would leave it for now and after 100 miles start playing with the stiffness as this will make a huge difference. On mine I have done as above and I am on click 9 out of 16 and I am very happy with the set up I was going up 3 clicks at a time until I was happy hope this has helped and enjoy the best mod you can do to the car