The factory jobs are fog lights, not driving lights...
If you never have to go through fog where you are, you can replace them w/driving lights, but, they'll be mounted too low for good long range (Driving) lighting....fog's are mounted lower, to cut under the fog better.
If you want to light up kamakaze critter eyes off the shoulder of the road, etc, aide in cornering vision at night, etc....then fogs or floods work well (Broader beam pattern).
If you want to light up signs 2 miles away, see upcoming corners, etc...then a longer range pattern would work...driving pattern like a long range headlight, or, if you want maximum range/minimum field of view (Long skinny pattern), a pencil or spot beam is better....and work best as high as possible.
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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