After some further research, it looks like the '08+ springs are 8" longer than the '99-07 Super Duties (which are the same length as the '80-97 trucks). I was originally planning on "B" code '99-07 rear springs as they're a direct drop in, but it looks like the '99-07 crowd is beginning to desire the '08+ swap for the better ride that it provides over their springs. Precision Metal Fab makes a bolt on bracket for the '99-07 trucks to accept the '08+ springs. I've contacted the shop to see if the bracket can be made to work on the OBS trucks. If the '08+ springs are better yet than the '99-07, It may be worth looking into what it takes to move my spring hanger forward for a two-fold increase in ride comfort.