My personal favorite are the Narva XB3 bulbs made in Germany. They put out a great white light, but do not require wiring/relay upgrades that should be done with high wattage bulbs ie. 100/90watt! The most expensive components to replace are your combo switches and having a failure in the middle of the night because you 'upgraded' to those high wattage bulbs without doing anything else to the electrical system is rather annoying at the least.
Also, remember that high wattage bulbs have a short life, especially the cheaper ones...you are their quality control.
It's kinda sad when I get contacted by folks that have installed the super wattage bulbs and now have smoked switches, ruined fuse boxes, or melted connectors.
If you use them install the upgrades...but the Narva bulbs are less expensive than all the other stuff! Good luck.
Midnightmoose.com H4 are only 39.95 for a set of housings and blubs. My cost was only 48.50 with shipping on first gen Z...
painless makes a relay kit that you can get from summitracing.com cost is around 71 but you take the load off the switch and old wiring and now get good 14 volts to the lights from your batt. spare bulbs are only 14.50 pick up an extra set when you order and if one goes out replace it... your total cost is still cheap and you will have VERY Bright lights...
Tip go to summit home page and hit the manf link jump to paniless go to the relay get the part number... back to summit page and search by summit part #
enter PRF-xxxxx where xxxxx = the part number you found on the painless page.