Are you talking "upgrading" to LED or HID bulbs in your halogen housings or replacing the whole assembly?
There no way to just swap the bulbs and still be legal and not be a danger to other drivers due to excessive glare.
If you're planning on changing the whole housing I can't really suggest anything, you'd be best served looking on a forum for your specific vehicle.
If you're looking at getting brighter bulbs you have a few options:
- Upgrade to better bulbs (not those stupid blue ones, actual, good quality bulbs)
- Build/buy a new wiring harness to get more power to the bulbs.
- Do both of the above.
The candle power forums and the Daniel Stern website are good places to start reading.