So I have finally finished all of the "got to do" things on the truck and can start working on some of the fun things. First up is dealing with my tired suspension. My end goal is to go with an OME 3" lift, since I'll be eventually installing bumpers/sliders. My question is this....can I replace my shocks now to improve the ride and then swap my springs later? I know it would be easier to do it all at once, but I don't mind taking things one step at a time as I can afford them.

 

I wouldn't. You will want longer shocks, and those probably won't work with your stock springs. You COULD get stock length shocks, and then get drop mounts and short shock towers, if they make that stuff for D2, but by the time you get all of that, you'll be pretty close to the cost of longer shocks.

Here is the 3" OME kit from Lucky 8. I've got a similar kit but from terrafirma

 

I agree, especially on the front axles, you will just be duplicating your work.
Exactly which OME springs are you looking at and be specific by spring number, cause you may be biting off more then you are ready for cause the true 3" OME lift, 751 front coils and 763 rear coils will beat you to death.
If anything, do 751 fronts and 762 rears along with D1 spring seats for the rear, this will give you nearly a 3" lift with a good ride in the back.