well, do the more basic, cheap stuff first to see if that does the trick. a lot of shops will probably hesitate cause its modding the OEM stuff and there may be a liability issue? or they are just ****ty mechanics... idk, doing sway bar quick discos is modding the OEM stuff, too. so thats prob not it...

 

give it time grasshopper, you'll start noticing grinding and rubbing and vibes, especially if you offroad any, that only makes things worse. I used to think the same thing, but was severly proven wrong after my last hard outing, fully flexed in the rear = unhappy tcase and yoke.

 

you can start with your driveshaft u-joints. they tend to wear a pattern then when you lift, you change the angle the pattern was worn in. so changing them may just rid you of the little vibe.

as for brand to use, spicer is the oem brand, which are very good quality, but cost quite a bit.
i usually just use napa premium or any other heavy duty non greasable type.

i'm over 5.5 inches with no t-case drop or sye and no vibes. just new joints every season.

 

Give it a shot man. I did mine without ever doing driveline mods before. The shaft is the only scary part. I cut mine a tiny bit off but it has held up fine to jumping and beating it like a red headed step child.