Just a heads up on the shackle flip, I have the shackle flip from ORD and I love it. Gives you the lift while still keeping the ride however because of the geometry of the shackle flip, your rear axle will move forward about 1.5". In order to correct this you need a zero rate add-a-leaf...
When you order shocks you need to give the fully extended length and a fully compressed length. I would go into a local shop and ask how to get proper measurements. The 5100s are great but I really like the 5150s. You will most likely get a better ride quality out of the 5150s over the 5100s if...