So what you're asking is a much more complex question than can be answered simply because there are too many variables associated with changing bulbs from one type to another, as well as the Kelvin color temperature difference, and finally (and probably most importantly) your individual perception of the light and what you're looking for out of your new setup.
A standard H11 bulb typically carries a 1350 lumen rating, you'll find standard headlamps anywhere from 1200-1400. If I'm looking at the same headlight kit on XD that you ordered, it's rated at 2500 lumens, so the baseline output of the bulb is much brighter.
However here are a couple of variables to consider: at least for the low beams, I assume you're going to be installing them in the standard 5th Gen halogen projectors. Since the geometry of the bulb itself is different (2 LED diodes placed back to back rather than on 360 degree halogen element) the light stands a chance of being thrown from the projectors differently. This COULD create noticeable dead spots where light isn't projected forward uniformly. The XD LEDs are designed to avoid this happening so I'm interested to see your results.
Secondly, the differences in Kelvin color temp could effect your perception of the lighting output. Halogen bulbs are usually around 3200K, fairly yellow light, especially compared to your new LEDs that are rated around 6000K, which is very white. This is particularly applicable to fog lights, which generally favor warmer / yellower Kelvin temps because that helps in inclement weather when they're designed for optimum use.
I've been watching a ton of lighting threads for quite a while now, and assembled most of what I've learned in the thread in my sig below. However, documentation on the XD (or any other) LED kit installed in the low beam spot is sort of lacking- I'm definitely interested to get your feedback as well as any before / after pics of the install and lighting differences between the kits once you get everything up and running.
Good luck.
