Yes, you will need/want caster correction. IMO, the yellow OME bushings are inadequate for a 3" lift, I would look into man-a-fre drop brackets or landtank brackets (not currently available, but in production) instead of the yellow bushings. Or there are other bushings on the market that might work. There are also trunion bearings that can be used to dial in some caster. Lots of options here, so do your research.
3" lift means different things to different people. There are tons of options with dual-rate springs, progressive rate springs, or constant-rate springs in various rates and stiffness. If you do go with OME, keep in mind that they do not sit level unless you have a ton of weight in the back. To get a level lift, pair a taller front spring with a shorter rear spring (eg: 850J front with 863 rear or 850 front with 860 rear).
Finally, it would behoove you to purchase from a reputable vendor who can answer your questions over the phone and get you properly set up, offer customer service if any problems arise. Don't try to save a buck by buying the cheapest thing you can find on amazon, it will not work out so well. I recommend
@cruiseroutfit or
@sleeoffroad