I've done something similar on one of my Z4s and difference is significant. I do need to get new brigther bulbs for this one. Will be doing the same on Z4M shortly.
https://www.zpost.com/forums/showthread.php?t=1656727
I should add that when the original projectors were removed there are two things I noticed that basically kill light output. The lens are dirty and its not a clear lens by design from factory. You can clean the lens however the reflector behind it is basically burnt out after years of use and you cannot fix this without replacing.