just want to give 2 cents worth. 60/55 = alternator rating = maximum output. if you upgrade your lights without upgrading everything else, the output of the higher wattaged bulb is not maximized since the alternator can only give off certain amount of power. i think it would be better to check for the real reason why you need to change your bulbs. baka naman malabo na ang reflector or foggy na ang lens or the bulb itself is already weak due to age. i know someone who mentioned that if you want to make the lights brighter by changing the bulbs, go for the lower wattage bulbs. this way, the output is maximized since your alternator or battery or wirings are still the same. i'm no expert but i can see my friend's point.