First, by all means do the headlight relay mod. That's the only way to get full voltage to your lamps, no matter which ones you end up with.
My recommendation for replacement lamps is unfortunately hard to find and well beyond your stated budget, but their performance is stellar. Cibie H4 E-codes are the best that I'm aware of. Many years ago I installed a set in my '66 Corvette and even with standard wattage, the results were outstanding. Daniel Stern sells them
http://www.danielsternlighting.com/home.html and a Google search might locate other, more affordable sources.
Good luck with whatever you get, but be sure to start with the relay mod.