what is the cheapest and brightest headlight upgrade i can do on my 04 ultra

 

I'd say the best value in $/lumens would be H.I.D. bulb/ballast retrofit into your existing bucket. That's what I did on my Dyna. About $30 got me way, way more usable light where I needed it. Not necessarily the highest quality illumination, mind you. But way more downstream lighting on the cheap.