h4 headlights

[reef166]

what size can i upgrade to without any problems

[caaf]

As in ADR? Anything apart from what is supplied by factory can attract problems.

If you mean globe wattage I would only increase in Kelvin and not increased amp's (due to the limited wiring that really can't handle the higher amps) Unless of course you have projector lenses, then I would consider HID 35watt around the 4300K as it would be at or near to 3100 lumen's. You find this to be near the best visual light, crisp and clear.