By definition, a Quad setup is a retrofit that uses four HID projectors. You can have four projectors retrofitted, but still have a Dual setup, if say one set of projectors are not HIDs.
So for a quad setup, you need four HID projectors that are on at all times. They can be all single xenon, or bixenon i.e. mini setup we just did, or a combination of single xenons and bixenons.
There are many options, and it really comes down to what you are looking for and budget.
The cheapest option would be four mini projectors like we just did and something like that will be just below/around $1100.
4 mini projectors isn't just an aesthetic upgrade, but an increase in light output by 100%.
If you want the best performing setup, then go with a set of mini bixenons and a set of s2000 projectors. You are now looking at about $1500 for a complete setup.
Hope this helps
Yes, that helped a lot. I had to do some more research on retro fits and xenon/bi-xenon projectors for a good couple weeks so I can learn and understand more about them. I think I'm just going to settle for a pair of Bi-Xenon projectors. I've been hearing good reviews on the FX-R Bi-Xenons and seen good reviews by you guys on the Mini H1 Bi-Xenon projectors. Now I need help. I'm sending my headlights off to a friend of my mine who works at Carbox Industries, and he said he is willing to do the retro fit but needs to know what set up I'd like to get first. Let me know what you'd prefer FX-R or Mini H1. Anymore info in addition with the answers, I'd like to thank you in advance!