My rig is at about 5", maybe 5.5", and I'm running a stock draglink and an RE tierod. Stock steering has been generally fine for my setup with the exception of places like Johnson Valley. I'm not likely going to invest any more money in this rig as I'm going to begin a new build this summer.
As for your tierod question, I'm not sure I would spend any more money on stock style setups if you truly think you're going to upgrade to something far better later. Just save your money and buy the stuff you really need. In the meantime, just keep a spare draglink and tierod handy when you're wheeling.