There is nothing wrong with the LP D30 for most wheeling. I see a lot of folks swapping to a HP, but in reality, unless you are seriously looking for a bit of ground clearance for the front u-joint, you are wasting your time.
I have a 01 XJ with 5.5" lift and 4.56's on 33s, no vibration issues. The axle is lunchbox locked. No Trusses, no issues.
Also have a LJ with 4.5" of lift with 3.73's on 33s, also no issues.
If you feel you need a D40 or a D60, just do it and skip the middle steps of buying aftermarket axle shafts, and eventually trussing it.
The difference is all about how you drive. I haven't broken a shaft in some number of years because I drive like I want to drive it home again... and I do.