I've installed the HID in the people 250, which shares the same housing. Although the light casted is much brighter in comparison, the reflector used in the kymco is total garbage and makes a terrible beam pattern (which is just less noticeable with the weaker halogen h4)
I went and put a sylvania silver star in, and it improved the function a bit after I got sick of the HID.
If you do go HID stay in the low range like 4000k, and get the bixenon kit bulb and harness, so you can retain your hi/lo function