Its less the quality issue, but the different lens.
A halogen projector has lens and its reflector bowl suited for a halogen bulb.
whereas a HID projector has lens/reflector suited for a HID Bulb.
In my opinion both types are .."illegal" like mine...even if you have a legit projector, it is not a part that comes standard for the car, plus there is no washer/leveling mechanism..
How much did your retro cost all up?
Here's some ball park figures
Spare set of headlights (aftermarket) 200, or 400 for genuine
HID Ballast (philips/hella/denso brand names) - $100-200
HID Bulb (philips or osram) - $100 per pair
Projectors:
my 1st projector (called TSX, comes from an accord euro) costs about $130
2nd set (called s2k, comes from an s2000) costs about $300
Shrouds/Bezel (optional):
These costs quite alot if you want superb one eg. BMW types (e46, used to be 90-100USD, now they are probably 150)
Its just a bit of reflective plastic. But you could probably get something else to cover the projectors. so this part is variable.
Misc: wires, relays, connectors, mounting materials, nuts/bolts etc... $20-30
and then there's the cutting/drilling work.
Cheers. So if you smash your headlights, you are up the **** creek right?
That is the main problem with retro fitting, if you damage them, its all back to square one again.
That is true - but if you have two sets of headlights,... it doesn't always have to be so bad...