upgrade the front shocks if you add the arb or shrock to the front of 2nd gen se??

If you would have to upgrade anything due to more weight it would be the springs. They support the weight. shocks support no weight they just dampen the action of the spring.

Most likely, stock shocks wont be able to support that weight for long

Doesn't hurt to upgrade while your upgrading your front too.

So far I've been ok with the drop in the front but as others have said I'm sure my fronts will wear out faster with the added weight.
Eventually, I will upgrade the fronts to raise the X up a little but for right now I'm quite happy with the ride quality, handling and ability to get where I want to go off road.
Last service the nissan techs said my front pads are about where they should be with my mileage so not seeing excessive wear on the brakes from the added weight.

I'd say it really depends on how you use your X, I'm more into overland exploration than running 4x4 trails for the sake of just conquering an obstacle.

Most likely, stock shocks wont be able to support that weight for long

Shocks don't have to support any weight....they just damp its motion, as already mentioned.

:D

Also as mentioned, the coils hold up the front end of the 2005 X, so that's what would tend to sag.

In real life, the aftermarket bumpers weigh ~ 100lb or so...and you REMOVE maybe 40-50 lb or so when you take OFF the OEM crap not needed anymore...so the actual weight change might be ~ 50 lb, unless you add a winch, which is of course all by itself ~ 75 - 100 lb or so.

Stiffer shocks are good to help damp the extra weight, and if you also lift, they can also help to control the extra forces due to the higher center of gravity, etc.

Of course, you don't HAVE TO do anything...but, if you wanted to, the measures can compensate for the mods.