Get what you pay for.. I retrofitted projectors into my truck and car and run Morimoto ballast,bulbs, and wiring harness. Very good quality and well worth the money.
I have installed DDMs for people before. I would never personally buy a set. They take a long time to warm up, flicker, every now and then one bulb wont ignite, and their customer service *****.
BTW dont run HIDs in reflector headlights. Even almost all of then projector headlights on
ebay are designed for halogen bulbs. So when you install HIDs you get odd patterns, blotchy light, and rough cutoffs.
The Retrofit Source online: headlight upgrades for all applications