Here you go:
http://www.purenissan.com/d22_control_arms.htm
After installing these UCAs, DO NOT torque the torsion bars until you're riding the bumpstops, as this will cause great strain on your axle cv joints (this assumes you have 4WD of course).
Regarding shocks, I use and like KYB monomax in my Xterra; but most people go with Bilsteins and like them. Just for comparative information: Xterra front stock shocks have a travel distance of 3.81"; KYB's (for lifted Xterra) have 3.93" travel; and Bilsteins (for lifted, I believe), have 3.88" travel.
Generally speaking, new UCA's and shocks won't give much, if any, extra wheel travel; however they will allow for maintained or improved ride quality with the 2-3" of front end lift achieved by cranking the torsions bars. The next purchase should be heavier duty torsion bars that can better tolerate harsh wheeling at the higher, tighter setting (cranked).
Also, the most common steering problem (mentioned up-thread) is the worn idler arm bushing.
Can buy here:
https://www.4x4parts.com/nissan/idler-arm-bushings-p-5257.html
Regarding the torsion bar re-indexing...this just relates to how much the adjustment anchors are tucked up within the frame cross-member. In other words, if you re-index your torsion bars, but then crank 'em until you have the same amount of front end lift as before re-indexing, then the only difference will be that the adjustment anchors will be hanging either lower to the ground (good for snagging on rocks), or more "tucked-in" to the cross member, depending on which way you rotated the torsion bar when doing the re-indexing.
Good luck!