Braddman recently posted a nice DIY about upgrading to HID. There is no question HIDs are the best technology available today for our headlights and it is a pity that smart does not offer HIDs as an option.
As for myself, I tested a cheaper, easier modification: replacing the smart H7 bulbs with OSRAM Rallye 65W Ultra High Output 2100 lumens bulbs vs. 1400 lumens for an ordinary H7.
Stock cutoff and pattern are maintained of course.
Bulbs are $25 to 30 each and the modification took me less than 5 minutes.
I took the smart for a quick drive through the neighborhood tonight and the difference is real: the illumination is whiter and more intense.
A last note of warning: those bulbs are not DOT approved. However, they do not cause any glare as the filament is exactly where it is suposed to be.
I shall try to post more relevant pictures (night time driving) in the coming days.