I'm guessing that a $15 sealed beam wouldn't light up the road like one o' those PIAA bulbs would. In my case I run 3 PIAA H4s because even my driving lights are hi/low. Now, I don't know how effective the stock lens is because I swapped that out too for an Adjure unit, but the PIAA bulb/Adjure lens combination seems to distribute light very effectively.
I researched HIDs but the jury is still out on them I figure for a number of reasons. LED is up and coming but I haven't researched that per se. But I am pleased with what the PIAA are capable of and I am waaaaaaaay ahead of anything stock.
