Does anyone know the light quality between the bumper mounted 20" vs roof mounted 40".
It really depends on what you're trying to do with it. But if you're looking for one light to do it all, I'd recommend a 40" on the roof over a 20" mounted on the bumper. As your buddy stated, the 40" will give you twice as much light, but the light will also be very usable because of the location. In my opinion, a 40" mounted to the roof with a combination spot and flood beam is a great setup. However, the disadvantages to this setup are: 1) you need to get wiring onto your roof to install it there. Even if you have the existing off road lights, the circuit can't handle the amperage draw of a typical 40" light bar (unless you go with a single row bar or something). 2) You will spill A LOT of light onto the windshield and hood, which makes it very difficult to see. This is even worse if you have a white or silver vehicle, and especially if you're running the combo flood/spot beam (but the flood does a great job of illuminating the sides of the roadway as you're driving, so it's desirable). Some people fabricate their own glare shields out of metal or plastic and install them along the bottom of the light bar to help with this. I actually found good luck with just installing a Vigg Designs hood blackout decal on the hood, but my lightbar is a little further back in my aftermarket roof rack than most setups so it doesn't spill onto the windshield at all.
Anybody else put a 50" on their Xterra ?
Or do most people opt for the 40" on the X ?
Most people run a 40" because it fits very well with brackets that attach to the OEM roof rack bolt locations. I have seen people run 50" bars though, but they either fabricated their own brackets, or used a bracket that mounts to the a-pillar (as knightrider mentioned) which is actually designed for the Navara.
Do cheap china brands come with brackets at all, or do I have to find these separately ?
For those that come with brackets, do they typically apply well on the X ?
Most will come with brackets that attach to the ends of the bar, but they are very generic and simple, and are designed for applications where the light bar is being mounted to a flat piece of metal. I've seen people drill into the wind faring to mount a 20" or 30" bar this way (along with a piece of metal behind the faring for strength), but a 40" would be too wide and would require some minor fabrication to make the included mounts work.
Does anyone have a good source for brackets for 40" (mounted above wind shield) or 50" (mounted on the A pillars) for the Xterra (1st gen) ?
Or am I looking at having to have brackets fabricated ?
In my opinion, the Offroad Gorilla brackets are hands down the best ones you can buy. I was running these on my factory roof rack with a 40" bar, and they're designed perfectly for our vehicles. They make several versions, depending on exactly how wide the light bar is and whether it's straight or curved. You can purchase them here:
http://www.offroadgorilla.com/shop/grrilla-light-bar-mounts
