I'm so f'n lazy. I installed 1 HIR bulb into my 4R last month, but haven't dragged my ass out to take some comp pics yet.
BTW: I bought the 65w bulbs, Toshiba HIR, from the ebay seller. Great service, and the light is waaaay brigher than 55w OEM bulb. I'll have to compare the 65w silverstar bulb that I have lying around to the HIR 65w too.
Summary: if you want WHITER light and shorter life, buy Silverstars. If you want BRIGHTER light with a (reported) longer life span, buy the HIR.
Although HIR are twice the price of SS, I'm not disappointed at all. I'd love to go HID, but I don't have 300-400 beans to blow on headlights right now. I just want to see betta.