I just recently installed the Umnitza 6000K upgrade for both the low beams and fogs (easy install, BTW) and have not found any issues with road illumination. That being said, it is well known that 6000K is not as "bright" as the OEM 4300K. It's just a little bluer in color and that translates to reduced brightness overall. You can search this subject on this board and get plenty of info.
-Dave
-Dave