After around 2.5 years of driving my LR4 with the H9 conversion, it's time for a long-term review.
The good:
* Much brighter than the stock halogens.
* Light source is the same size, shape, and location as the stock halogens, so it puts the light where it's supposed to go on the road.
* Relatively cheap.
* Doesn't require any modification to the vehicle, and only a slight modification to the bulb.
* Only tool required is a dremel (recommended) or a maybe a small file.
The bad:
* The H9 bulbs only last around 6 months, pretty much requiring you to carry spares at all times. Swapping the bulbs on an LR4 isn't too difficult and doesn't require any tools, but it's still a drag to have a burnt out bulb. Headlight bulbs just never really burn out at convenient times.
* Still not as bright as xenon.
* Still not as "cool" as xenon.
The verdict:
Nothing can really be done to make the halogen housing be as bright as xenon or be as "cool" as xenon, save doing an illegal and not-recommended HID conversion, so the main downside is the short lifespan of the bulbs. The extra light more than makes up for this problem, though.
What now?
Since I bought my LR4 I've been keeping a lookout for a set of xenon housings. New, they'd run close to $2,000. I negotiated a used set on eBay for $500. EDIT: To anyone reading this, make sure you buy housings that are Non-Adaptive.
A stock LR4 comes with Osram 66340 xenon bulbs in the size "D3S;" at least that was what were in the housings I received. Those bulbs are rated at a "Lifespan B3" of 2,000 hours, and a "Lifespan Tc" of 4,000 hours. This means that 97% of these bulbs go at least 2,000 hours, but 63% of these bulbs will have failed by the time they reach 4,000 hours.
I'm not sure what year of LR4 my housings were from, or how long they've been "out of service." Given these housings were used, and could have come from as old as a 2010 model, the xenon bulbs could be nearing the end of their lifespan. Additionally, xenon bulbs, even if they don't fail, get dimmer over time, so I wanted to put some fresh bulbs in to start at peak brightness with my new-to-me xenon housings. Therefore, I ordered some new Phillips D3S bulbs from HIDBulbsRUs.com. From what I gather, it's really easy to get fake, Chinese GE, Osram, or Phillips bulbs online, but HIDBulbsrUs came recommended as a legit source of genuine bulbs by candlepowerforums, which is pretty much the preeminent authority on lighting on the internet. These bulbs were $48 each shipped, which is a price that cannot be beat.
So, after I cleaned up my xenon housings, I put in the Phillips bulbs and hooked it all up to my LR4. To my surprise, the headlights seemed to work correctly even before I used my iiD tool to change my ECU to reflect I that I now had xenon bulbs. Nonetheless, I used the iiD Tool to make the adjustment, then waited until dark to test the lights.
And really, it should go without saying that the xenon headlamps are vastly superior to the halogen headlights, even with the H9 conversion.
So much superior, in fact, that I cannot believe Rover offered both. 3200 lumens (xenon) is obviously much brighter than the 2,000 lumens (H9 bulbs) and much, much brighter than ~1,100 lumens (stock halogen bulbs).
The obvious downside is cost. All told, the parts cost me around $600 ($500 for the used xenon housings and $100 for the new Phillips bulbs). Add to that the cost of the iiD tool, which you will need unless you have a good relationship with your dealer, and it's a pretty pricey way to upgrade your headlights. Still, though, it's clearly the *best* upgrade you can do to the LR4's halogen headlights, and I expect I could sell my old halogen housings on eBay and recoup some of the cost.
I suspect many who have a '10 to '13 LR4 with halogen housings would rather just go ahead and facelift their LR4 to a '14+ look on the front, and I can't really blame them. PowerfulUK sells some good parts to do this upgrade, and even sells a filler piece (sold out right now) that would allow you to do it without changing your bumper (only changing the headlights and the grille).
That said, although the '14+ headlights look cooler, they are functionally not as good as the '10 to '13 headlights, as the low-beam and high-beam cannot be on at the same time in the newer model as they can in the older model.
But really, that's a minor concern.