The low beam on the 04 4Runner is a 9006 bulb. I would recommend our
9006 Xtreme HID kit. The kit does come with a relay harness if you choose to power the lights straight from the battery rather than the vehicle wiring. Our kits are 35W and use a very low draw ballast so you can safely connect to the factory wiring with just the bulb and ballast if you don't want to use a relay. The relay is purely optional on the 4Runner.
John