I had OEM projectors on my last car Mazda RX-8 and they were very nice, put out a lot of light, but this specific kit from V-LEDs is larger and puts out far more light than those OEM, and the built in hi/low switch that moves the internal shield on this specific kit is much better than the typical OEM halogen hi beams.
Once you get around to spending 5x the time in labor and R&D on your homemade kit we can compare output levels and especially the aiming of the beams which you do not have to worry with this kit ;-) For me this was the perfect solution to wanting some type of projector without the risk of ruining the stock housings with R&D. And it is just a huge plus that you don't have to worry with aiming problems or the hi beam problems that most OEM conversions would have, and the light output is far better than the OEM's I have experienced. Seems pointless to me to put in R&D on something that has already been made to fit, but to each their own :-)