You must buy six sets. Three for you and three for the other guy approaching you from the front. Sir, I'm a huge fan of HIDs but not at the cost of blinding someone. Do you know the health problems HIDs lights cause for the on-lookers? Sudden rise in Blood Pressure if he is hypertensive, vertigo and Migraine. The trick is to use them in a balanced way. Use the fogs first till the time you feel they are not enough then switch them off and turn on low beam. As for Highways, well, I guess you know what to do.
I bought generic ones but with CAN-BUS technology for 4500/-. Am a happy camper now.