Back in the rally car days, I used the conversion H4 type. I used Bosch, Marchel, and Cibie at different times over the years. I liked them all. You could choose the intensity (wattage) of the lamp to install in the units. At some point you could have so much wattage that your stock alternator could not keep up with the load. I was especially impressed with the Cibie "Z" beams. The light pattern illuminated to the max far down the road on your side, but cut back and under the oncoming traffic on the other side of the road.