I have a 03 350z touring and I bought the 06+ bixenon headlights on here a couple months back and swapped them. Before the 55 watt hids, I had the stock oem 35 watt ballasts running 8k aftermarket bulbs on the new lights with sti retrofit. But I was still not 100% percent satisfied with the light output.
And to me and others technology advances daily and for their to be newer generated 55 watt HID ballasts I just had to do it.

 

Yeah I bet the higher wattage HID will get you a lot more output... Glad to hear you like it. Keep in mind your bulbs will not last as long though pumping that much power into them. But hopefully its worth it, light output vs. bulb replacement interval.