I think that statement is misleading, your stock shafts may be fine depending on what type of springs you get. Most people choose to push the front axle forward to help with firewall clearance. If that's the case, you more than likely will run out of slip yoke on the front shaft. More importantly, your front shaft's CV yoke on the tcase will be unable to function at ride height let alone full droop. You will need to clearance it or buy a high angle CV.
No one yet really asked the clarifying questions regarding lift type, usage, etc. to answer your question properly.
Regardless, I would stay away from cheap springs, tcase drop brackets, brake line drop brackets, blocks, and lean more towards shackle flips along with crossover steering at that lift height.