The 5-link is a superior design as it eliminates the goofy 3-link they had before with the so-so quality ball joint. A 3-like is simpler but that's about all it has going for it.
I like solid front axles under trucks but no amount of bitching is going to get the OEM's to switch back. (Ford excluded

)
JD used the RR Heep spacers.
The Boondox ones shouldn't sag, hell, polyurethane is far more dense than suspension rubber. If not, ask the original designer of Boondox's spacers:
http://www.k9rdj.co.uk/vitara/vitlift.htmI just get the feeling RR's spacers loose some integrity when you bore out the center hole, not to mention due to the geometry of the front Jeep springs have FAR lower spring rates than a Track/Kick/Vit/GV/etc front springs have.
I've got NAPA nitrogen truck shocks for the front of a FJ60 Land Cruiser on the rear of the GV. About $20 each and fit great with the 2" lift. MUCH stiffer and larger than the stock shocks but they don't seem to hit the axle or anything else even when I cycle it. I'll have to check the panhard bar though.