A lot depends on your preferences for control versus ride comfort...a stiffer shock means better control, less body lean, faster recovery, and a harsher ride...
A softer shock is more comfortable, but also more floaty, etc.
If you think you might add more weight (Skids, bumpers, fatter kids, carbs...etc...) the extra stiffness now might be handy later.
If you and yours will always remain the same weight, you can bias towards comfort or handling as you prefer.
I have 20% extended Bils on with the 3" SL...and they ride great as far as I'm concerned, way better than the stockers did.
I had Shrockworks bumper and sliders, a winch, and equipment riding around before the lift, on the OEM shocks,...and going up 3" for SL + onto 33 x12.5's, I thought the overall responsiveness of the handling improved.
If that helps.

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- TJ
2001 Xterra '03 VG33, SE 5 spd, 305/70/16's, Revolvers, UBSkidderz, Doubled AAL's, 3"SL/2"BL, winch/bumpers, skids, sliders, OBA, Snorkel, pine stripes....
Friends don't let friends drive stock.
http://www.gifsoup.com/view/501230/tj-tackling-crawlers-ridge-o.gif