There are a lot of different varieties of Halogen lights. If they are the 'real' high output style you need to add a relay as the current draw is too much for the factory system and the circuit breaker will pop after you've been on 'high' for a little while. If you just have the halogen replacements (with the non-replaceable bulbs) then it's not an issue - but still an improvement.
I live in deer country (unreal deer country) and early evening driving means 'all eyeballs at the windshield'..... I'm not sure I can explain just how 'serious' it is around here.... whap, whap, all the time to bambi.