I use 5w-30 Mobil1 fully synthetic.
Yeah, that clunking noise is common. Its the floating calipers, and that noise is the pads moving when you press on the brakes. You will hear it, fowards and backwards. Some say they hear it on rough roads.
What kind of HID conversion kit did you get?
Look in the F.S. forums to find discounts. Here in the states, we can get the part # from Lexus and call Toyota for better pricing.