The part number depends on lift size, for a 3-4" lift I Think these are the numbers I have written down.
But these may have been numbers from the vendor and not Bilstein.
I got mine from a guy on the Jeep Forum by the name of Kolak. He is highly recommended on that board and gave me the best price I could find and delivered quick. Contact him with your questions and lift and he will give you what you need.
I can say the Bilstein 5100's along with my RE Extreme 4.5 has made my Jeep handle better and more comfortable than it has ever been. Remember the shocks will only be as good as the springs and other parts of the suspension, they won't make crappy springs ride nice or articulate better.
Here is his info email@example.com