I also own a modded Brinyte B158B with a d-domed XP-G2 S4 2B and it does 330kcd without a collar. I think the B158B is generally a very nice light. The plastic lens is a big benefit because it is light and the quality is always good.
I also own a modded Z1. Because of it’s size, the massive brass pill and the glass lens it’s much heavier. Almost too heavy for the jacket pocket. The lens is also smaller than the B158B lens, so it will get less throw. The quality of the light is great except for one thing: the focussing bezel is very loose when the light is not at full focus. Everytime I pick up the light the focus changes a little bit. It also requires much more turning of the bezel to get to flood mode and back compared to the B158B because it doesn’t have the special, steep threads.