There are two points I have found:

1. Drive line angle. Which ever SYE you get, there will be a change in driveshaft length. That change, coupled with any lift, will change your driveline angle. Shims are the quick and easy fix. However, shims may not be enough. In that case, relocation of spring perches is necessary. And, if you go with shims, use steel shims (check Pro-Comp for their shims). Most shims are aluminum and (IMHO) will not last.

2. Rear axle drop. Keep in mind that the CV joint has a centering pin that is only about 3/8 inches in diameter. It will break if you are in a situation where full axle drop puts full weight load on the CV joint. I broke 2 within a 2 month period. Now I have limiter straps so that axle drop is limited to keep full weight off of the centering pin.