If you're truly looking for better lighting, the HID's in OEM housings designed for halogen bulbs are probably your biggest problem. Said another way, they just don't work. Yes, a good HID bulb is brighter than a halogen, but you need the rest of the optical system to be designed to utilize and project that light. That's not the case with the OEM housings for a number of technical reasons. That's also why most OEM HID headlights are projectors.
So, are the Alpharex (or other Chinese) units actually better? Be careful. Many of those units are designed to put out large amounts of foreground light to fool you into thinking they are actually better. A certain amount of foreground light is indeed desirable, but you also need distance lighting so as to avoid the issue of "over-driving your headlights." That's where your headlights don't project far enough for you to see the deer standing in the road in front of you.