Over the past twenty years I have utilized 80 watt bulbs on low beam and 100 watt bulbs on high beam, and these higher-wattage bulbs have required the use of an aftermarket harness which features a relay as well as a circuit breaker and/or fuse. I never had any problems with blinding other drivers as I made sure the headlights were aimed properly and of course I used high beams as required. I would suggest that anyone contemplating the installation of higher-wattage bulbs in their SMART first have a look at Daniel Stern's website for additional information:
http://www.danielsternlighting.com/[