I've been using the Silverstar Ultra for a few weeks now, not had any wiring issues that I know of and gives off noticably more light. The literature says H4 compatible or words to that effect and is the same 60/55 watt rating as the OEM bulb. I can't see there being any problems with wiring if the wattage remains the same. My concern with the Ultra was they may not last long due to the vibrations and bumpy roads. So far so good but they're not cheap, 69.00 dollars for two at Canadian Tire. Good luck.
