I have 35 watt 6000K HIDs in my vn calais and they are heaps better than the standard globe. Used the cheap kits you get off ebay from hong kong and havent had a problem. U need to buy Hi/Low switching H4 globes and then H3 for the 2 high beam globes.
HIDs can throw off a little more glare than the standard globe as the reflector was not designed for HID globes. All I did was adjust the headlights down a touch so i am not blinding other drivers.
As a mechanic I have had to repair the fuse and relay wiring for the headlights on a couple of VNs due to bigger wattage globes being used. The aging electrical wiring and extra load put on it can cause fuse and relay holders to melt.
The 35 watt HID globes run cooler than the standard 55 watt globe, put out more light and use less power once warmed up. The only downfall from having them is they take a good 10 seconds to warm up which can be a pain when you need the full power from your high beams when you put them on, not 10 seconds later. Plus you still have to take into account the reflector in the headlight was not designed for HID globes so installing them will make the car unroadworthy.